Fuck up an Anvil

Someone who could fuck up the simplest of requests.

An ability to screw up simple tasks. Commonly written out as "X could fuck up an anvil" it is meant to imply a thing that should otherwise be unbreakable is not safe with them. A common revision of the insult involves adding the words "with a rubber mallet," as the fact that rubber is softer than steel means it should be impossible for a rubber mallet to do any damage to a steel anvil.