The Key blade of Laughter

The  Keyblade of Laughter is the Keyblade that Pinkie Pie possesses the element of laughter. The Keychain is a blue balloon-shaped gem that looks similar to her cutie mark with a gold plating around it.

Kingdom Hearts
The Keyblade first came to be after Pinkie pie and her friends wished that they could help Sora, Donald, and Goofy fight the Heartless that invaded Equestria, which helped Sora, Donald, and Goofy in beating the Heartless and finding Equestria's Keyhole.

Design
The Keyblade is depicted as a classic  skeleton key  approximately 3.5' long, with a long silver Keychain extending from the hilt, and The Gem of   Laughter on the end of the Keychain. The blade and teeth of the Keyblade are three big circles, two baby blue and one yellow between the baby blue circles, and the guard is mostly baby blue with yellow lines circling around it.