Stretch (Shy Guy)

Stretches are enemies that are encountered in Super Mario World 2: Yoshi's Island and its remake Yoshi's Island: Super Mario Advance 3. These variants of Shy-Guys are taller and thinner than ordinary Shy-Guys, with additional hair on their head. Yoshi cannot defeat them by jumping on them; instead, when jumped on, Stretches get flattened and spit out watermelon seeds. If Yoshi keeps at least one of these Shy-Guys around, he can easily take out other enemies nearby. They are very rare, and are only encountered in two levels.

Super Mario World 2: Yoshi's Island

 * Official Nintendo Player's Guide: Jump or pound Stretch and he'll lay low until you step off. Then, he'll pop back into shape.