Mystery transaction in block 299506 -- Can it be spent?

[keatonatron]

Hey all,

I noticed this transaction: https://blockchain.info/tx/136becd0892fa38c5aca8104db8b90b3a0e6b40912b7d1462aed583c067054cd

It kind of looks like the output script is saying, as long as you provide a valid multisig for any address you can spend it (the wiki says OP_MULTISIG drops one item from the stack, so I'm guessing the OP_NOT just gets ignored. If not, does it mean anything that isn't a multisig is usable??)

Is this transaction spendable? Does OP_MULTISIG even work when it isn't a multisig address?

[telepatheic]

Yes it is spendable by placing an invalid signature followed by some pub keys.

Code:

0 <invalid-sig> 1 <pub1> <pub2> 2

will spend the transaction.

[keatonatron]

Nice. Why are the public keys required? Shouldn't anything that fails the multisig check work, or does OP_MULTISIG error out if it doesn't have them? (e.g. NULL != FALSE)