Whittles are a species of wood-like humanoids in the Mario series. They do not speak proper English, but yet are helpful allies to Mario and Luigi.
Super Mario Galaxy 2
Whittles first appear in Super Mario Galaxy 2 as allies found in the Tall Trunk Galaxy as their homeland. They they are the ones who have taught Mario about the Blimp Fruit which turns Yoshi into his Blimp form and ask Mario to go down the giant slide in another episode of the Tall Trunk Galaxy so they may test his courage. They go down that same slide to test their courage too. If Mario completes the dangerous slide, a Whittle at the bottom of the slide rewards him with a Power Star. After Mario completes Tall Trunk Galaxy, one goes on Starship Mario. There is also a giant tree in the galaxy on which the Whittles describe it as sacred. One of them also teaches Mario to use the Cloud Flower in Fluffy Bluff Galaxy.
Mario Party 9
Whittles are confirmed to appear in Mario Party 9 as they are seen in a mini-game involving chopping wood.
Whittle's name comes from whittle which means to carve something out of wood.