The Fire Punch is a melee weapon in Worms 4: Mayhem. When equipped, the Worm will have any hats replaced by a red bandana, until the end of their turn. The melee animation is an uppercut, which sends the enemy flying several feet and doing 28 damage.
There is a glitch with the Fire Punch which allows the user to send enemies flying much farther than usual and doing at least double the damage. It involves having the enemy worm to the side, but having the image in the top right say that you will hit. You must face as far away from the enemy as possible. The reason why is that the enemy worm hits the player's worm multiple times, increasing launch distance exponentially. If executed properly, the worm will fly at least as far is if in contact with a double-damage influenced explosion. They will also take at least 60 damage.