Poochy

Poochy is a dog that has appeared throughout the Yoshi series. He occasionally shows up in levels to serve as a rideable platform of sorts, able to walk over terrain such as spikes and lava that Yoshis usually cannot walk on without being damaged. He has a spotted coat with a long red tongue, duck lips and red (yellow in Yoshi's Woolly World) ball at the end of his tail. He barks constantly while he walks.

Super Mario World 2: Yoshi's Island / Yoshi's Island: Super Mario Advance 3
Poochy makes his first appearance in Super Mario World 2: Yoshi's Island and reappears in the remake, Yoshi's Island: Super Mario Advance 3 (receiving no changes besides a graphical update). He is able to run on hazardous forms of terrain and charge though any enemies in his path. Poochy is ridden by jumping on his head and looking in the intended direction. He attempts to follow the Yoshi riding him wherever they go, waiting under them if he cannot jump to their location, though he does not enter Warp Pipes and doors. He can also swim through water while carrying Yoshi. If Poochy reaches a wall, he crosses through a gap if one is present (which usually only fits him and not Yoshi), and otherwise tries to jump over it, even if he is not able to make it across, though Yoshi can jump off of his head while he is jumping. He can be distracted by throwing an egg at his head, which he plays with and ends up not paying attention to anything else.

Poochy only appears in three levels: first in 1-Extra, Poochy Ain't Stupid, and later in 2-1, Visit Koopa And Para-Koopa, and 3-2, Jungle Rhythm....

Tetris Attack
Poochy appears in Tetris Attack alongside a Grinder as one of Yoshi's opponents. He was originally Yoshi's friend, but went against him due to a spell cast by Bowser and Kamek that brainwashed him. Once Yoshi defeats him (which involves playing the game's panel-based puzzles against him), he and Grinder are broken from the spell and joins Yoshi as he fights against Bowser. He is then unlocked as a playable character that can fight against the other brainwashed characters, though there is no difference in gameplay, only the appearance of the player's side and the sounds that play as panels are matched (cheerful barks as opposed to Yoshi's voice).

Yoshi's Story
Poochy also appears in several levels of Yoshi's Story, helping the Baby Yoshis along the way. Although the Baby Yoshis are not able to ride on top of him, Poochy is able to find hidden fruits. In the levels he appears in, Poochy usually starts chained to a post that can only be removed by Ground Pounding on it, thus breaking the chain and freeing Poochy. After being released, Poochy runs through the level and sniffs out items that are hidden; when Poochy discovers something, he stands by the spot and barks. They can be revealed by ground pounding. After the item is revealed, Poochy moves on to sniff out other hidden items.

Yoshi's New Island
Poochy returns once again in Yoshi's New Island, regaining his ability to walk on hazardous obstacles from Super Mario World 2: Yoshi's Island. He also behaves and is able to be controlled as previously, though he is now able to smash through certain types of blocks and grab items (such as keys) that the Yoshi can then take. He makes only two appearances in the game: first in 3-5, Don't Fear the Spear, which lets him demonstrate his new abilities, then in 4-S, See Poochy Run!, where he must be used to clear the stage while avoiding maces and spikes.

Yoshi's Woolly World
Poochy returns in Yoshi's Woolly World appearing in numerous levels and functioning nearly identical as in previous installments, though two Yoshis are able to ride him now and they sit on his back rather than stand. To go with the game's wool motif, Poochy has a knitted appearance. A buyable Power Badge makes him available in any stage, though since his usefulness is very situational, it costs only 500 beads to use the badge, making it the cheapest one in the game.

Club Nintendo
Poochy makes a cameo in the Club Nintendo comic Rummelplatzquatsch. He appears on the screen of Mario's Game Boy Camera, which supposedly tells the future. After Poochy shows up on the screen, a herd of dogs comes running towards Luigi and urinate on him.

Mario Kart: Double Dash!!
In Mario Kart: Double Dash!!, Poochy makes a cameo in the background of the Baby Park racetrack, though only in the decoration, and does not make a physical appearance otherwise.

Mario Party Advance
A gaddget named Poochy Pal appears in Mario Party Advance. It involves Poochy walking (and sometimes sleeping) around a backyard and interacting with the various objects in it, such as a Warp Pipe that he can enter. The player has no control over what Poochy does.

Super Mario-Kun
Poochy appears as a supporting character in volumes 19 and 20 of the Coro Coro Comics manga Super Mario-Kun. When he first appears, Red Yoshi mistakes him for an enemy and eats him. Red Yoshi releases him in an egg after Mario reprimands him and Poochy emerges unharmed. He accompanies Mario and the six baby Yoshis on their quest to retrieve the Super Happy Tree, and forms a special friendship with Yellow Yoshi.

Poochy appears in volume 19 chapter 5, 愛犬ポチ！みんあのためにかんばるワン！！ (Beloved Poochy! The dog who does his best for everyone!!), and is the central figure in the events of that chapter.

A different Poochy made his first appearance in the volume 4 of Super Mario-Kun.

Trivia

 * Poochy appears in a pre-release screenshot of Paper Mario, but he is absent from the final game.