Ukikis are monkeys that spit watermelon seeds at Yoshi in Super Mario World 2: Yoshi's Island (although in that game it was called "Grinder"). He is seen with Poochy in Tetris Attack. He also is a hat-stealing thief in Super Mario 64 or Super Mario 64 DS, where he'll steal Mario, Luigi, or Wario's hat if one of them gets too close. Mario, Luigi, or Wario will have to chase the Ukiki down to get his hat back, and if Mario doesn't get it back, Ukiki will always be wearing it on the level Tall, Tall Mountain. Also in Super Mario 64 and Super Mario 64 DS, Mario, Luigi, Yoshi, or Wario will have to chase Ukiki onto the Monkey Cage where the star is, then the cage will then release the Star.
Ukikis also make an appearance in Mario Party 4, Mario Party 5, Mario Party 6, Mario Party 7, and Mario Party Advance. In Mario Party 4, he'll be in a mini-game where he throws bananas. In Mario Party 6, he may help the player out in a snowball fight if he/she is in a 1 in a 1 vs. 3 mini game. In Mario Party Advance, a couple of them will be in the game, one of them, Ukiki, is the mayor of Jungle Town, the other is his niece, Akiki.