Ukiki
Ukikis, sometimes called Ukkikis (with two Ks), are monkeys, that look like Grinders. They first appeared in Super Mario 64. There are two Ukiki seen in that game, living on 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. However 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, and he will jump on a cage with a star for him.
Ukikis have also appeared in the Mario Party series. In Mario Party 4, they toss a banana. This banana, upon being slipped on, will determine a character's path around the game board.
In Mario Party 5 they were revealed to also come in other colors: gray, blue, red and very rare gold ones. They were also a capsule that would when activated would use a characters capsules. In Mario Party 6 Ukiki appeared in Castaway Bay hosting a special coin collecting mini game. In Mario Party 7 (Where they appeared look like Grinders), Ukikis cameoed in the background of the Mini-game Cruise, cleaning Peach's Cruiser.
In Mario Party 8, Ukikis appeared in DK's Treetop Temple, where they would roll down the stage on barrels, taking ten coins from anyone in their path. Mechanical Ukikis appeared in the mini-game Flip the Chimp. Also in the battle mini-game Snipe for the Picking there are two ukikis turning cranks. In Mario Party Advance, a Ukiki named Akiki (who happens to be the niece of an individual Ukiki who is named "Ukiki") appears.
Ukikis also appear in other Mario titles, like Mario Power Tennis, where they appear in the background of a court.
A similar-looking monkey called Grinders also appeared in Yoshi's Island; it's unknown if they're related.
