Igashira-kun

Screenshot of Yoshi with two Spikeballs.

A Spikeball is a round, spike-covered enemy that appear in Yoshi Topsy-Turvy. If the Game Boy Advance is tilted left or right, they will awaken and roll to the accordingly direction, and if the Game Boy Advance isn't tilted, they won't roll and will fall asleep. They deal three points of damage when Yoshi touches one. Spikeballs can also defeat other enemies, like Shy Guy and some that Yoshi can't by himself, like Tap-Tap. Spikeballs can also be found in wire-like constructs floating in mid-air, where they regularly move across.