Wendy O. Koopa is a boss Paper Mario: Color Splash. She is the fourth Koopaling to be encountered by Mario and is overall the seventh boss of the game.
She is part of the Koopa Troop, and notably one of the seven Koopalings. She guards the Purple Big Paint Star found in the Purple Region. Mario encounters her deep in the caves of Fortune Island. She will poetically greet Mario, then initiate a battle with him. Once defeated, Mario is able to retrieve the Purple Big Paint Star.
During battle, Wendy can summon a chest or clam, which will open up and spew either enemies or coins. Wendy will then attack Mario with said objects. After several regular attacks, Wendy will summon a ring to immobilize Mario. The Instant Camera must be used right before the attack so that the ring will instead immobilize a snapshot of Mario. If Mario does not use the Instant Camera and becomes trapped in the ring, he will instantly die. If the snapshot is trapped, Wendy will shatter the ring into coins and the attack will fail. After the attack, the fight will progress as usual.
- Wendy's firepower-based ability is a stand off to most other firepower-based abilities used by the Koopalings previously fought before and later after Wendy (aside from Morton Koopa Jr. who has no firepower-based abilities), as unlike the others, who's firepower are energy based, Wendy uses Enemies and Coins as firepower.
- The battle with Wendy is very similar to Gooper Blooper from the previous game, Paper Mario Sticker Star, seeing as both bosses have a music-theme vibe in them, both bosses tap at their music and both require a Thing Sticker to block their specie attack.
- Coincidentally, both bosses are fought in a Chapter that has boats.
- In Mario and Luigi: Paper Jam, at some point Wendy and Roy ponder over whether Koopalings have Paper counterparts. This is possibly foreshadowing the Koopalings debut in the Paper Mario series in Paper Mario: Color Splash, which came out the year after.