Croak Hopper

Croak Hopper (クロークホッパー) is a big frog enemy, carrying a smaller one in its back, that appears in Wire Sponge's stage in Mega Man X2 and Mega Man Xtreme 2. It was originally created to be the mascot of the Weather Control Center and are often found near Weather Crystals. Similar to real frogs, their behaviour is affected by the temperature of the current weather:
 * On normal weather, they remain static and shoot a three-way shot at intruders. In Mega Man Xtreme 2, it is a two-way shot when playing as Mega Man X, and a sole shot when as Zero.
 * On warm weather, they overheat and explode as real frogs are ectotherms. The lack of warm weather in Mega Man Xtreme 2 prevents it from overheating.
 * On rainy weather, they actively hop around while the smaller frog on their back jumps and falls right in place. If the player contacts the smaller frog, it will explode.
 * On foggy weather, they will hide and don't even appear on screen.

Due to their weakness to high temperatures, the Speed Burner automatically eradicates them, though Magnet Mine and Sonic Slicer are also very effective.

Other Media
Croak Hoppers appear in the Rockman X2 manga in the Weather Control Center alongside Scrivers, Sky Farmers, Sole Solars, and Sabotteins.

Trivia

 * For unknown reasons, the smaller frog on its back is blue in the artwork, but green in-game.
 * During the development of Mega Man X2, Croak Hoppers were used as placeholders for some enemies in the Desert Base Stage and Deep-Sea Base Stage.

Similar enemies

 * Kerog
 * Kerosh
 * Onbuubattan