diff --git a/packages/types/src/index.spec.ts b/packages/types/src/index.spec.ts
index 124d905946..b7027fff00 100644
--- a/packages/types/src/index.spec.ts
+++ b/packages/types/src/index.spec.ts
@@ -16,7 +16,11 @@ import * as definitions from './interfaces/definitions';
 // specifically for the types that _should_ throw in the constrtuctor, i.e
 // `usize` is not allowed (runtime incompat) and `origin` is not passed through
 // to any calls. All other types _must_ pass and allow for empty defaults
-const UNCONSTRUCTABLE = ['genericorigin', 'origin', 'usize'];
+const UNCONSTRUCTABLE = [
+  'ExtrinsicUnknown', 'GenericExtrinsicUnknown',
+  'GenericOrigin', 'Origin',
+  'usize'
+].map((v): string => v.toLowerCase());
 
 function testTypes (type: string, typeNames: string[]): void {
   describe(type, (): void => {
diff --git a/packages/types/src/interfaceRegistry.ts b/packages/types/src/interfaceRegistry.ts
index a030b1132e..c30b0541b0 100644
--- a/packages/types/src/interfaceRegistry.ts
+++ b/packages/types/src/interfaceRegistry.ts
@@ -3,7 +3,7 @@
 
 import { Compact, Option, Vec } from './codec';
 import { Bytes, Data, Fixed64, H160, H256, H512, Null, StorageData, StorageHasher, StorageKey, Text, Type, bool, i128, i16, i256, i32, i64, i8, u128, u16, u256, u32, u64, u8, usize } from './primitive';
-import { AccountId, AccountIdOf, AccountIndex, Address, AssetId, Balance, BalanceOf, Block, BlockNumber, Call, Consensus, ConsensusEngineId, Digest, DigestItem, Ed25519Signature, Extrinsic, ExtrinsicEra, ExtrinsicPayload, Hash, Header, ImmortalEra, Index, Justification, KeyTypeId, KeyValue, LockIdentifier, Moment, MortalEra, Origin, Perbill, Permill, Phantom, PhantomData, PreRuntime, Seal, SealV0, Signature, SignedBlock, Sr25519Signature, ValidatorId, Weight, WeightMultiplier } from './interfaces/runtime';
+import { AccountId, AccountIdOf, AccountIndex, Address, AssetId, Balance, BalanceOf, Block, BlockNumber, Call, Consensus, ConsensusEngineId, Digest, DigestItem, Ed25519Signature, Extrinsic, ExtrinsicEra, ExtrinsicPayload, ExtrinsicUnknown, Hash, Header, ImmortalEra, Index, Justification, KeyTypeId, KeyValue, LockIdentifier, Moment, MortalEra, Origin, Perbill, Permill, Phantom, PhantomData, PreRuntime, Seal, SealV0, Signature, SignedBlock, Sr25519Signature, ValidatorId, Weight, WeightMultiplier } from './interfaces/runtime';
 import { InclusionHeight, Uncle, UncleEntryItem } from './interfaces/authorship';
 import { RawAuraPreDigest } from './interfaces/aura';
 import { BabeAuthorityWeight, BabeBlockWeight, BabeWeight, RawBabePreDigest, RawBabePreDigestPrimary, RawBabePreDigestSecondary, SlotNumber } from './interfaces/babe';
@@ -167,6 +167,9 @@ export interface InterfaceRegistry {
   ExtrinsicPayload: ExtrinsicPayload;
   'Option<ExtrinsicPayload>': Option<ExtrinsicPayload>;
   'Vec<ExtrinsicPayload>': Vec<ExtrinsicPayload>;
+  ExtrinsicUnknown: ExtrinsicUnknown;
+  'Option<ExtrinsicUnknown>': Option<ExtrinsicUnknown>;
+  'Vec<ExtrinsicUnknown>': Vec<ExtrinsicUnknown>;
   Hash: Hash;
   'Option<Hash>': Option<Hash>;
   'Vec<Hash>': Vec<Hash>;
diff --git a/packages/types/src/interfaces/runtime/definitions.ts b/packages/types/src/interfaces/runtime/definitions.ts
index b649b7186f..0485b1c6ae 100644
--- a/packages/types/src/interfaces/runtime/definitions.ts
+++ b/packages/types/src/interfaces/runtime/definitions.ts
@@ -20,6 +20,7 @@ export default {
     Extrinsic: 'GenericExtrinsic',
     ExtrinsicEra: 'GenericExtrinsicEra',
     ExtrinsicPayload: 'GenericExtrinsicPayload',
+    ExtrinsicUnknown: 'GenericExtrinsicUnknown',
     Hash: 'H256',
     Header: {
       parentHash: 'Hash',
diff --git a/packages/types/src/interfaces/runtime/types.ts b/packages/types/src/interfaces/runtime/types.ts
index 73ee7ff94e..b637b2869e 100644
--- a/packages/types/src/interfaces/runtime/types.ts
+++ b/packages/types/src/interfaces/runtime/types.ts
@@ -3,7 +3,7 @@
 
 import { Codec } from '../../types';
 import { Compact, Struct } from '../../codec';
-import { Bytes, Fixed64, GenericAccountId, GenericAccountIndex, GenericAddress, GenericBlock, GenericCall, GenericConsensusEngineId, GenericDigest, GenericDigestItem, GenericExtrinsic, GenericExtrinsicEra, GenericExtrinsicPayload, GenericImmortalEra, GenericMortalEra, GenericOrigin, H256, H512, Null, StorageData, StorageKey, u128, u32, u64 } from '../../primitive';
+import { Bytes, Fixed64, GenericAccountId, GenericAccountIndex, GenericAddress, GenericBlock, GenericCall, GenericConsensusEngineId, GenericDigest, GenericDigestItem, GenericExtrinsic, GenericExtrinsicEra, GenericExtrinsicPayload, GenericExtrinsicUnknown, GenericImmortalEra, GenericMortalEra, GenericOrigin, H256, H512, Null, StorageData, StorageKey, u128, u32, u64 } from '../../primitive';
 
 /** GenericAccountId */
 export type AccountId = GenericAccountId;
@@ -59,6 +59,9 @@ export type ExtrinsicEra = GenericExtrinsicEra;
 /** GenericExtrinsicPayload */
 export type ExtrinsicPayload = GenericExtrinsicPayload;
 
+/** GenericExtrinsicUnknown */
+export type ExtrinsicUnknown = GenericExtrinsicUnknown;
+
 /** H256 */
 export type Hash = H256;
 
diff --git a/packages/types/src/primitive/Extrinsic/Extrinsic.ts b/packages/types/src/primitive/Extrinsic/Extrinsic.ts
index 86fd105796..cc9ae72820 100644
--- a/packages/types/src/primitive/Extrinsic/Extrinsic.ts
+++ b/packages/types/src/primitive/Extrinsic/Extrinsic.ts
@@ -3,12 +3,13 @@
 // of the Apache-2.0 license. See the LICENSE file for details.
 
 import { FunctionMetadataV7 } from '../../interfaces/metadata/types';
-import { Address, Balance, Call, Index } from '../../interfaces/runtime';
+import { Address, Balance, Call, ExtrinsicUnknown, Index } from '../../interfaces/runtime';
 import { AnyU8a, ArgsDef, Codec, ExtrinsicPayloadValue, IExtrinsic, IHash, IKeyringPair, SignatureOptions } from '../../types';
+import { ExtrinsicOptions } from './types';
 
 import { assert, isHex, isU8a, u8aConcat, u8aToHex, u8aToU8a } from '@polkadot/util';
 
-import { ClassOf } from '../../codec/create';
+import { createType, ClassOf } from '../../codec/create';
 import Base from '../../codec/Base';
 import Compact from '../../codec/Compact';
 import ExtrinsicV1, { ExtrinsicValueV1 } from './v1/Extrinsic';
@@ -17,9 +18,13 @@ import ExtrinsicV3, { ExtrinsicValueV3 } from './v3/Extrinsic';
 import ExtrinsicEra from './ExtrinsicEra';
 import { BIT_SIGNED, BIT_UNSIGNED, DEFAULT_VERSION, UNMASK_VERSION } from './constants';
 
+// We use this type internally to cast the raw value since ExtrinsicUnknown does not actually properly
+// implement an Extrinsic - by design, it just throws on construction, allowing for overrides
+type ExtrinsicVx = ExtrinsicV1 | ExtrinsicV2 | ExtrinsicV3;
+
 type ExtrinsicValue = ExtrinsicValueV1 | ExtrinsicValueV2 | ExtrinsicValueV3;
 
-interface ExtrinsicOptions {
+interface CreateOptions {
   version?: number;
 }
 
@@ -35,28 +40,29 @@ interface ExtrinsicOptions {
  * - signed, to create a transaction
  * - left as is, to create an inherent
  */
-export default class Extrinsic extends Base<ExtrinsicV1 | ExtrinsicV2 | ExtrinsicV3> implements IExtrinsic {
-  public constructor (value: Extrinsic | ExtrinsicValue | AnyU8a | Call | undefined, { version }: ExtrinsicOptions = {}) {
+export default class Extrinsic extends Base<ExtrinsicVx | ExtrinsicUnknown> implements IExtrinsic {
+  public constructor (value: Extrinsic | ExtrinsicValue | AnyU8a | Call | undefined, { version }: CreateOptions = {}) {
     super(Extrinsic.decodeExtrinsic(value, version));
   }
 
-  private static newFromValue (value: any, version: number): ExtrinsicV1 | ExtrinsicV2 | ExtrinsicV3 {
+  private static newFromValue (value: any, version: number): ExtrinsicVx | ExtrinsicUnknown {
     if (value instanceof Extrinsic) {
       return value.raw;
     }
 
     const isSigned = (version & BIT_SIGNED) === BIT_SIGNED;
     const type = version & UNMASK_VERSION;
+    const options: ExtrinsicOptions = { isSigned, version };
 
     switch (type) {
-      case 1: return new ExtrinsicV1(value, { isSigned });
-      case 2: return new ExtrinsicV2(value, { isSigned });
-      case 3: return new ExtrinsicV3(value, { isSigned });
-      default: throw new Error(`Unsupported extrinsic version ${type}`);
+      case 1: return new ExtrinsicV1(value, options);
+      case 2: return new ExtrinsicV2(value, options);
+      case 3: return new ExtrinsicV3(value, options);
+      default: return createType('ExtrinsicUnknown', value, options);
     }
   }
 
-  public static decodeExtrinsic (value: Extrinsic | ExtrinsicValue | AnyU8a | Call | undefined, version: number = DEFAULT_VERSION): ExtrinsicV1 | ExtrinsicV2 | ExtrinsicV3 {
+  public static decodeExtrinsic (value: Extrinsic | ExtrinsicValue | AnyU8a | Call | undefined, version: number = DEFAULT_VERSION): ExtrinsicVx | ExtrinsicUnknown {
     if (Array.isArray(value) || isHex(value)) {
       // Instead of the block below, it should simply be:
       // return Extrinsic.decodeExtrinsic(hexToU8a(value as string));
@@ -91,7 +97,7 @@ export default class Extrinsic extends Base<ExtrinsicV1 | ExtrinsicV2 | Extrinsi
     return Extrinsic.newFromValue(value, version);
   }
 
-  private static decodeU8a (value: Uint8Array): ExtrinsicV1 | ExtrinsicV2 | ExtrinsicV3 {
+  private static decodeU8a (value: Uint8Array): ExtrinsicVx | ExtrinsicUnknown {
     return Extrinsic.newFromValue(value.subarray(1), value[0]);
   }
 
@@ -127,7 +133,7 @@ export default class Extrinsic extends Base<ExtrinsicV1 | ExtrinsicV2 | Extrinsi
    * @description The era for thios extrinsic
    */
   public get era (): ExtrinsicEra {
-    return this.raw.signature.era;
+    return (this.raw as ExtrinsicVx).signature.era;
   }
 
   /**
@@ -148,7 +154,7 @@ export default class Extrinsic extends Base<ExtrinsicV1 | ExtrinsicV2 | Extrinsi
    * @description `true` id the extrinsic is signed
    */
   public get isSigned (): boolean {
-    return this.raw.signature.isSigned;
+    return (this.raw as ExtrinsicVx).signature.isSigned;
   }
 
   /**
@@ -169,42 +175,42 @@ export default class Extrinsic extends Base<ExtrinsicV1 | ExtrinsicV2 | Extrinsi
    * @description The [[Call]] this extrinsic wraps
    */
   public get method (): Call {
-    return this.raw.method;
+    return (this.raw as ExtrinsicVx).method;
   }
 
   /**
    * @description The nonce for this extrinsic
    */
   public get nonce (): Compact<Index> {
-    return this.raw.signature.nonce;
+    return (this.raw as ExtrinsicVx).signature.nonce;
   }
 
   /**
    * @description The [[ExtrinsicSignature]]
    */
   public get signature (): IHash {
-    return this.raw.signature.signature;
+    return (this.raw as ExtrinsicVx).signature.signature;
   }
 
   /**
    * @description The [[Address]] that signed
    */
   public get signer (): Address {
-    return this.raw.signature.signer;
+    return (this.raw as ExtrinsicVx).signature.signer;
   }
 
   /**
    * @description Forwards compat
    */
   public get tip (): Compact<Balance> {
-    return this.raw.signature.tip;
+    return (this.raw as ExtrinsicVx).signature.tip;
   }
 
   /**
    * @description Returns the raw transaction version (not flagged with signing information)
   */
   public get type (): number {
-    return this.raw.version;
+    return (this.raw as ExtrinsicVx).version;
   }
 
   /**
@@ -238,7 +244,7 @@ export default class Extrinsic extends Base<ExtrinsicV1 | ExtrinsicV2 | Extrinsi
       };
     }
 
-    this.raw.addSignature(signer, signature, payload);
+    (this.raw as ExtrinsicVx).addSignature(signer, signature, payload);
 
     return this;
   }
@@ -247,7 +253,7 @@ export default class Extrinsic extends Base<ExtrinsicV1 | ExtrinsicV2 | Extrinsi
    * @description Sign the extrinsic with a specific keypair
    */
   public sign (account: IKeyringPair, options: SignatureOptions): Extrinsic {
-    this.raw.sign(account, options);
+    (this.raw as ExtrinsicVx).sign(account, options);
 
     return this;
   }
diff --git a/packages/types/src/primitive/Extrinsic/ExtrinsicUnknown.ts b/packages/types/src/primitive/Extrinsic/ExtrinsicUnknown.ts
new file mode 100644
index 0000000000..ffef92df1c
--- /dev/null
+++ b/packages/types/src/primitive/Extrinsic/ExtrinsicUnknown.ts
@@ -0,0 +1,21 @@
+// Copyright 2017-2019 @polkadot/types authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import { ExtrinsicOptions } from './types';
+
+import Struct from '../../codec/Struct';
+import { UNMASK_VERSION } from './constants';
+
+/**
+ * @name ExtrinsicUnknown
+ * @description
+ * A default handler for extrinsics where the version is not known (default throw)
+ */
+export default class ExtrinsicUnknown extends Struct {
+  public constructor (value?: any, { isSigned = false, version = 0 }: Partial<ExtrinsicOptions> = {}) {
+    super({});
+
+    throw new Error(`Unsupported ${isSigned ? '' : 'un'}signed extrinsic version ${version & UNMASK_VERSION}`);
+  }
+}
diff --git a/packages/types/src/primitive/Extrinsic/index.ts b/packages/types/src/primitive/Extrinsic/index.ts
index 7ff156a5c6..ffa0998cd5 100644
--- a/packages/types/src/primitive/Extrinsic/index.ts
+++ b/packages/types/src/primitive/Extrinsic/index.ts
@@ -5,3 +5,4 @@
 export { default as GenericExtrinsic } from './Extrinsic';
 export { default as GenericExtrinsicEra, MortalEra as GenericMortalEra, ImmortalEra as GenericImmortalEra } from './ExtrinsicEra';
 export { default as GenericExtrinsicPayload } from './ExtrinsicPayload';
+export { default as GenericExtrinsicUnknown } from './ExtrinsicUnknown';
diff --git a/packages/types/src/primitive/Extrinsic/types.ts b/packages/types/src/primitive/Extrinsic/types.ts
index 66388556bd..8c1849aeeb 100644
--- a/packages/types/src/primitive/Extrinsic/types.ts
+++ b/packages/types/src/primitive/Extrinsic/types.ts
@@ -5,7 +5,8 @@
 import { AnyNumber } from '../../types';
 
 export interface ExtrinsicOptions {
-  isSigned?: boolean;
+  isSigned: boolean;
+  version: number;
 }
 
 export interface ExtrinsicSignatureOptions {
diff --git a/packages/types/src/primitive/Extrinsic/v1/Extrinsic.ts b/packages/types/src/primitive/Extrinsic/v1/Extrinsic.ts
index d895aaa3a8..1f984d4758 100644
--- a/packages/types/src/primitive/Extrinsic/v1/Extrinsic.ts
+++ b/packages/types/src/primitive/Extrinsic/v1/Extrinsic.ts
@@ -25,7 +25,7 @@ const TRANSACTION_VERSION = 1;
  * The first generation of compact extrinsics
  */
 export default class ExtrinsicV1 extends Struct implements IExtrinsicImpl {
-  public constructor (value?: Uint8Array | ExtrinsicValueV1, { isSigned }: ExtrinsicOptions = {}) {
+  public constructor (value?: Uint8Array | ExtrinsicValueV1, { isSigned }: Partial<ExtrinsicOptions> = {}) {
     super({
       signature: ExtrinsicSignatureV1,
       method: 'Call'
diff --git a/packages/types/src/primitive/Extrinsic/v2/Extrinsic.ts b/packages/types/src/primitive/Extrinsic/v2/Extrinsic.ts
index c688cdf8e5..2a41c61927 100644
--- a/packages/types/src/primitive/Extrinsic/v2/Extrinsic.ts
+++ b/packages/types/src/primitive/Extrinsic/v2/Extrinsic.ts
@@ -25,7 +25,7 @@ export interface ExtrinsicValueV2 {
  * The second generation of compact extrinsics
  */
 export default class ExtrinsicV2 extends Struct implements IExtrinsicImpl {
-  public constructor (value?: Uint8Array | ExtrinsicValueV2 | Call, { isSigned }: ExtrinsicOptions = {}) {
+  public constructor (value?: Uint8Array | ExtrinsicValueV2 | Call, { isSigned }: Partial<ExtrinsicOptions> = {}) {
     super({
       signature: ExtrinsicSignatureV2,
       method: 'Call'
diff --git a/packages/types/src/primitive/Extrinsic/v3/Extrinsic.ts b/packages/types/src/primitive/Extrinsic/v3/Extrinsic.ts
index 03e60c03ea..7796774da5 100644
--- a/packages/types/src/primitive/Extrinsic/v3/Extrinsic.ts
+++ b/packages/types/src/primitive/Extrinsic/v3/Extrinsic.ts
@@ -22,10 +22,10 @@ export interface ExtrinsicValueV3 {
 /**
  * @name ExtrinsicV3
  * @description
- * The second generation of compact extrinsics
+ * The third generation of compact extrinsics
  */
 export default class ExtrinsicV3 extends Struct implements IExtrinsicImpl {
-  public constructor (value?: Uint8Array | ExtrinsicValueV3 | Call, { isSigned }: ExtrinsicOptions = {}) {
+  public constructor (value?: Uint8Array | ExtrinsicValueV3 | Call, { isSigned }: Partial<ExtrinsicOptions> = {}) {
     super({
       signature: ExtrinsicSignatureV3,
       method: 'Call'