Grinders (also called Monkeys or Ukikis) are enemies in the game Super Mario World 2: Yoshi's Island. They can attack Yoshi in many random ways, such as spitting seeds or dropping bombs and dropping Needlenoses. These two Grinders are called Seedy Sallys and Short Fuses respectively. They can even steal Baby Mario. Most Grinders however tend to run away from Yoshi. They mostly appear in World 3 of the game.
Grinders are also seen in Yoshi's Island DS this time, they are completely harmless and are among the weakest enemies in the game as they cannot harm Yoshi. After the defeat of Gilbert the Gooey, a group of Grinders overwhelm Yoshi and kidnap Baby Mario and Baby Peach. Yoshi then gives chase and meets Baby Donkey Kong who jumps on his back and helps him rescue the Babies and stop the Grinders. They only appear in World 2-1 and World 2-7. The Seedy Sallys and Short Fuses are completely absent in this game, also the Grinders never try to steal the babies during actual gameplay making them merely an egg supply rather than an actual enemy.
Grinders return in Yoshi's New Island with the exact same role as the original game, commonly found in various levels of World 3.
In Yoshi's Woolly World Grinders act the same as before from previous games but cannot steal Baby Mario due to the fact that he does not appear in this game exclusively in the level A Little Light Snowfall Grinders can attack by throwing snowballs at Yoshi.
In Yoshi's Crafted World Grinder reprise their role from previous games and are often found on vines a new variant of Grinder can toss Yoshi Eggs for Yoshi this marks the first time that the Seedy Sally variant doesn’t appear they only appear in the levels Jumping to Victory and Bombs Away on Pirate Island.