From the Super Mario Wiki
Glad Parabombs are enemies found on Vibe Island in the game, Super Princess Peach. They are just like regular Parabombs and float down to the ground with parachutes, but once they land, they act like Glad Bob-omb rather than regular Bob-ombs.
According to the game's Glossary, "It gets happy when it loses its parachute. Then it skips."