Question: where are the star coins in rise of the piranha plants?
Answer: Star Coin 1: Not too far from the start of the level, the first Star Coin is found above a Big Piranha Plant. ... 
Star Coin 2: In a Warp Pipe guarded by a Big Piranha Plant, the player must use a Fire Flower to defeat it and the other Piranha Plants beyond the Warp Pipe.