The Hydra is a monster encountered in the My Little Pony: Friendship Is Magic episode "Feeling Pinkie Keen". It was based upon the mythological water-dragon of Greek antiquity and resided within a large swamp called "Froggy Bottom Bogg", on the outskirts of Ponyville.
While they find Fluttershy, the ponies note a smelly gas that envelops it as it rises from the bog. The monster rise and before chasing the ponies, it gives a threatening roar and licks its lips. The heads sometimes display different expressions and even laugh at each others' misfortunes. Twilight, Applejack, Fluttershy, Pinkie Pie, and Spike run away from the hydra, and it sticks out one of its tongues at the ponies after they successfully escape.
It has four heads on long snake-like necks and a large, orange, dragon-like body, with only two legs and no wings or arms.
- The hydra's first introduction is similar to the one featured in Disney's Hercules.
- Some of its roars are from the original Sharptooth
- It is never mentioned if something is done about the Hydra after the episode. Twilight does not seem to mention it in her letter to Princess Celestia.
- It is similar to the first two phases of the final battle with the Leech Hydroe in Hey! Pikmin, because when the chase begins it is buried in the swamp water, but then its full body and legs emerges from the water.
- In the season eight episode "Molt Down", Smolder mentions that molting dragons are prey to hydras.