The Body Iron

Donkey Kong is granted with this mighty weapon, The Body Iron! Instead of just being a big hammer the Body Iron is actually a magical weapon in which the head of the hammer changes size to match the size of its target. The head changes right before impact. I know DK has his bongos but I had this weapon in mind and he was the only person suitable for it.

Mario's weapon: desirino.deviantart.com/art/Th…
Luigi's weapon: desirino.deviantart.com/art/Gr…
Waluigi's weapon: desirino.deviantart.com/art/Th…
Toad's weapon: desirino.deviantart.com/art/Sh…