Train Bandit

A Train Bandit is a chalk Shy-Guy etched onto certain walls in the game Super Mario World 2: Yoshi's Island and its remake Yoshi's Island: Super Mario Advance 3. When Yoshi has transformed into the Train, Train Bandits come to life and chase after him. They are limited to the walls' borders and stop moving when Yoshi returns to his normal state. The only ways to defeat a Train Bandit are by using the Winged Cloud Maker, Anywhere POW, or by smashing a POW Block when they are on-screen, with the latter only being possible in the Game Boy Advance version, in Go! Go! Morphing!.

Super Mario World 2: Yoshi's Island

 * Shogakukan guide: 壁から抜け出して追いかけてくる. ダッシュで逃げよう. (They will come out of the wall and chase you. Dash to escape.)
 * Player's Guide: These pistol-packing varmints try to hold up Yoshi after he's morphed into a steam engine.

Yoshi's Island: Super Mario Advance 3

 * Shogakukan guide: ヨッシーがきかんしゃに変身する場所に出現. レールを走っていると、かべからぬけ出して追いかけてくる. 倒せないのでダッシュで逃げろ！ (They appear in places where Yoshi transforms into a train. When you travel along a rail, they will escape from the wall and chase after you. You can't beat them, so dash away!)