Wispy Woods

Pre-Locked Rooms
At some point in time, he was captured and mind controlled by Mr. L.

Season 2
He blocks the door to the next stage, and after being miserably defeated, he uses cybernetic enhancements to become WISPY NEO.

Wispy Woods
Wispy has only been shown to fire apples.

WISPY NEO
WISPY NEO can fire apple missiles.

Trivia

 * Wispy NEO is based off of Alphys NEO from Undertale.