From the Super Mario Wiki
“Ook...oookiii! (I used your capsules!)”
Super Mario World 2: Yoshi's Island / Yoshi's Island: Super Mario Advance 3
Ukikis first appeared in Super Mario World 2: Yoshi's Island and its remake, Yoshi's Island: Super Mario Advance 3. They usually show up in jungle stages and attack Yoshi in a variety of ways, including spitting seeds, dropping bombs, and grabbing Baby Mario; when hit, they turn a darker shade of brown and run away. Some are harmless and simply run around the stage, acting as a source of eggs. Fleeing Ukikis jump onto vines and climb them as high as possible, jumping off and running if a Yoshi gets too close. Ukikis can also swim slowly in water. Ukikis can be stunned with eggs or a stomp, after which Yoshi can defeat them by eating them or running over them while they are unconscious. However, they are difficult to eat while running because of their speed. Ukikis cannot be defeated while in water, as stunning them instead causes them to "flail" in place.
An Ukiki appears in Tetris Attack alongside Poochy in every mode as one of Yoshi's opponents. Due to a spell cast by Bowser and Kamek that brainwashed them, they tried to stop Yoshi on his adventure to stop Bowser. Once the Ukiki is defeated, he and Poochy are freed from the spell and are unlocked as playable characters, though Poochy is used for the icon and the sound effects during gameplay.
Yoshi's Island DS
Ukikis make a reappearance in Yoshi's Island DS. One of them kidnaps Baby Peach at the beginning of the level Baby DK, the Jungle King!, which is the only level that they appear in. They are all harmless, but are still difficult to catch due to their agility. If a Yoshi goes near them, they immediately run away or climb away on nearby vines, though they usually stop once they make it off-screen.
Yoshi's New Island
They once again appear in Yoshi's New Island. In this game, Ukikis cannot be eaten (though they can still be defeated by other means, such as a Ground Pound), and are prominent in the stages Ukiki Jammin' and Ukiki Trouble in Clawdaddy Cove, though they also appear in other levels of World 3, including Rise of the Nasty Nep-Enuts, Harry Hedgehog's Labyrinth, and Ride the Blarggwich. They remain almost entirely unchanged from Super Mario World 2: Yoshi's Island
Yoshi's Woolly World
Super Mario series
Super Mario 64
In Super Mario 64, two Ukikis (spelled Ukkiki) inhabit Tall, Tall Mountain. One can be seen following Mario around and doing tricks. However, if Mario grabs him, he will steal Mario's hat and wear it. To get it back, Mario has to grab him again; this is made difficult by the fact that Ukiki now runs away from Mario. In the second mission of Tall, Tall Mountain, Mario has to catch a different Ukiki on the very top of the mountain; when caught, the monkey will jump on a cage with a star for Mario, making it accessible.
Super Mario 64 DS
In the remake Super Mario 64 DS, if any character was wearing another character's hat, the monkey would take it and the character would transform back into himself. A glitch allowed Wario to pick up Ukiki using the Metal Cap and could even carry him into the water. In this game, they have their more distinguished mischievous faces from Yoshi's Island as opposed to the basic, round-headed 3D model from the original version.
Mario Party series
Mario Party 4
In Mario Party 4, Ukikis make an appearance, keeping their look from Super Mario 64. They appear on Koopa's Seaside Soiree, on two junctions on either side of the board. Once a player reaches it, an Ukiki tosses a banana peel that the player immediately slips on. They are forced to continue in whichever direction they slipped in. Ukikis also appear in the minigame Tree Stomp, in which they throw banana peels at players , cheering if one of them slips. They occasionally throw a golden banana that makes any player who picks it up move faster for a while.
Mario Party 5
In Mario Party 5, they appear in the minigame Chimp Chase, in which four variants of Ukikis make an appearance: gray, blue, red and very rare gold ones. Besides a difference in appearance, they all behave the same. In the minigame, baby Ukikis are running around, and they have to be grabbed and delivered to the adult Ukiki that is colored correspondingly to it. Delivering a baby to the wrong adult makes them scream, paralyzing the player who delivered the baby and freezing all of the baby Ukikis of the same colour. Golden baby Ukikis occasionally appear, running much faster than the others, and not only can they be delivered to any adult, but they are also worth more than the others. A Ukiki Capsule also appears; using it, whether by throwing it onto a space and landing on it or used directly on the player for ten coins, summons an Ukiki that randomly selects another player and throws all of their capsules onto random board spaces.
Mario Party 6
In Mario Party 6, Ukikis appeared in Castaway Bay hosting a special coin collecting minigame. They also appeared in various minigames such as Snow Brawl, where they act as allies to the solitary player, and Strawberry Shortfuse, where they deliver plates with either cake or explosives. They also appear in the Memory Quiz, the Variety Quiz, the Comparison Quiz and the Counting Quiz of Speak Up.
Mario Party 7
In Mario Party 7, Ukikis cameoed in the background of the Minigame Cruise, cleaning Peach's Cruiser. They also appear in the Apes of Wrath minigame. As of this game, Ukikis began to consistently appear in their Yoshi's Island design.
Mario Party 8
In Mario Party 8, Ukikis appear in DK's Treetop Temple, where they are summoned if a player lands on an Event Space. They roll down the stage on barrels, knocking over anyone in their path and taking ten coins from them. Mechanical Ukikis appear in the minigame Flip the Chimp, with each player controlling an Ukiki; they have to make their Ukiki climb to the top of a tree while avoiding falling coconuts. They also appear in the battle minigame Snipe for the Picking, where two Ukikis are seen turning cranks in the introductory cutscene, and in the duel minigame Cardiators on the "2" card and the "6" card. If the "2" card is chosen, a single Ukiki attacks the opposing player for two damage, and if the "6" card is chosen, three Ukikis attack the opposing player for six damage.
Mario Party Advance
Two Ukiki characters appear in Mario Party Advance: Ukiki, the mayor of the Jungle Area, and Akiki, Ukiki's niece. The two of them live in the Ukiki House. Generic Ukikis also appear in the minigame See Monkey?, which involves saving ten Ukikis from drowning in a lake while the player rides in a boat. Once the player come into contact with an Ukiki, they are given a lifebuoy and get attached to the boat. The minigame is failed if any of the Ukikis are missed once the time limit runs out.
Dance Dance Revolution Mario Mix
Ukikis have made appearances in several games, including Mario Power Tennis, Mario Superstar Baseball, Mario Super Sluggers, and Mario Strikers Charged, as members of the audience, though they do nothing but cheer. The name "Ukiki" also appears on the scoreboard in Mario Golf for the Nintendo 64 and Mario Golf for the Game Boy Color.
Names in other languages