Dead Parrot Defense

When a lie or excuses is so blatantly ridiculous and unbelievable, the defendant has no choice but to stick to his/her absurd defense, disregarding all possible logic/laws of physics/obvious contradictions. Taken from the Monty Python dead parrot sketch in which a shop owner insists a clearly dead parrot is alive.

Tim got caught cheating on his girlfriend, but stuck to a dead parrot defense of she was an out of work actress and he was helping her with simulated sex scenes