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.
"Did Mike just touch the thing with the big sign right next to it that says
'do not touch?'"
"Yeah. Mike ... Mike could
fuck up an anvil."
"With
a rubber hammer."
