you have to do something
2 get Petey piranha on Mario power tennis complete GIMMICK MASTERS:THUNDER CUP in DOUBLES then it will say yu unlocked Petey piranha
u cant
No. Petey Piranha is only in Mario Kart: Double Dash!!.
Don't kill Petey Piranha but anyways... ground pound on Petey Piranha, of course.
You can't unlock Petey Piranha in Mario Kart DS. It is myth character, and you could probably only obtain him if you sprite hacked and made some manual changes on the game. The four chanarcters which you can unlock on Mario Kart DS are Daisy, Dry Bones, Waluigi, and R.O.B. You can also obtain Shy Guy from hacks.
You can't get R.O.B or Petey Piranha on Mario Kart Wii, but you get Toadette by "Playing on all 32 courses in Time Trials mode or winning 1,000 Wi-Fi online matches." You don't have to unlock the Koopa Troopa. He's already there!
1. Super Mario Sunshine 2. Mario Power Tennis (Tic-Tac-Glow) 3. Mario Kart: Double Dash That's all of them I guess.
Win Mirror Star Cup. This also unlocks The Piranha Pipes Kart and King Boo.
Beat Petey Piranha as Mini Mario.
Petey Piranha's (and King Boo's) special item in Mario Kart: Double Dash!! is randomly the special item of any other character.
Defeat Petey Piranha (W5 Boss) as Mini Mario.
To defeat Petey Piranha, you must fill him up with water while his mouth is open. Then you must ground pound on his stomach when he falls over.