Banana Charm summons and dismisses Bananas, a baby ape pet that follows you around, meaning it is a non-combat pet and will not aid you in battle.
This item is available only to those who receive the King Mukla card in the World of Warcraft Through the Dark Portal TCG expansion that has the "scratch off gently" strip. Once you scratch and reveal the code, you can turn it in to Landro Longshot in Booty Bay who will give you Banana Charm.
A sample Bananas pet exists as a neutral level 1 beast near Landro Longshot.
This pet is also a possible drop from [Landro's Pet Box] (also a TCG item).