Wik

Wiks are tiny undead fireballs that first appear in Yoshi's Woolly World. They are found in World 2-7, The Desert Pyramid Beckons!, and World 4-6, Spooky Scraps! Don't Get Spooked!, flying up and down, making them very similar to Cloud Drops from previous Yoshi's Island games. If a Wik is covered by a Spooky Scrap, it will appear much more aggressive, move slightly faster and become invincible. As a result, they can hurt Yoshi if he touches it in this state, although they can be defeated by throwing a yarn ball at them while they are uncovered. In the same reason, Wiks can also turn into white yarn if Yoshi eats them.

Trivia

 * Wiks get their name from "candle wick", the string that holds the flame of a candle.