Paper Mario first appeared in Paper Mario for the Nintendo 64 console. Since then he's made cameos and sequels like Paper Mario: The Thousand-Year Door for GameCube and Super Paper Mario for Wii.
Super Smash Bros. Melee
Paper Mario appeared as a trophy.
Super Smash Bros. Brawl
Paper Mario can be obtained as a regular trophy.
A legendary hero whose adventure unfolds when he sets out to rescue Princess Peach from the nefarious clutches of Count Bleck. He has the ability to flip the world from 2-D to 3-D and back again. If he grabs a Mega Star, he'll transform into a pixelated giant Mario. In this state, he's invulnerable and capable of stomping through enemies and obstacles with ease.