Piranha Gun

The Piranha Gun is a ranged weapon added in Update 1.2. It is found inside Jungle Chests, which can only be found in Dungeons. This weapon fires a piranha-shaped projectile that latches onto an enemy to do continuous damage while the attack button is being held. The fire pattern is very similar to the Chain Knife, but with a much longer range. The projectile will proceed to attack another enemy (if any is near) when it has killed its target, otherwise it has to travel back to the gun before it can be fired again.

Trivia

 * This gun is likely a reference to a weapon used by the character Vector from Despicable Me. It's a bit easier to get the ammo back in, though.