Oh, in that case a lob wedge is in fact the club of choice if you are brave enough to get within ~3 arms lengths of the zombies as they are hella sharp when you turn them sideways.
Alternatively, a bladed set of clubs are pretty sharp as is and a 3 iron is long enough to stand further away from the zombies and still cause major damage. [see below for examples]

Lob wedge, note the sharp edge.

Bladed irons, sharp edged again but longer shaft for greater safety when dealing with zombies [more difficult to use for real golf though].