Treevil

Treevil is a walking tree enemy found in Mario & Luigi: Bowser's Inside Story. It appears in two forms, one with sad glowing blue eyes, and one with malicious red eyes, holding an acorn on its branches; these Treevils are stronger. To attack, a Treevil throws twigs at the character. While playing as Bowser, Treevil will either lob the twig high into the air, forcing Bowser to use his shell defence, or throw it so it bounces along the ground, upon which Bowser must counter it with a punch. If a Treevil has an acorn, Bowser can inhale it using his Vacuum attack to restore 20 HP. When Mario and Luigi encounter a Treevil, it attacks in the same way, but the bros. must counter the twigs with their hammers.

Trivia

 * "Treevil" is a portmanteau of the words "tree" and "evil."
 * They bear a resemblance to the trees with eyes seen in Forever Forest in Paper Mario.