Hector the Reflector

"Mirror, mirror on the wall, I've got a friend who's the ghastliest of them all! Are you frightened yet, little Yoshi?"

- Kamek

Hector the Reflector is the third boss of Yoshi's Island DS. He is a strange, egg-shaped ghost that resides in a Ghost House-like fort (to be more specific, he lives at Hector the Reflector's Haunted House) filled with Boos, possessed furniture, and other supernatural creatures. His fight is unusual, taking into effect the full potential of each screen. When the fight begins, he is invisible on the top screen, but visible on the bottom. Yoshi can peek into the "mirror" bottom screen, find Hector, and then throw an egg at him on the top. After each hit, Hector throws a flowerpot at the bottom screen, "cracking" it. His Invisighoul minions also pick up furniture and fling it at Yoshi, but Yoshi can eat it for more eggs. After six hits, he vanishes, granting Yoshi access to the next level.

Trivia

 * Hector the Reflector gets his name from the mirror part of the battle: he is reflected in the mirror, but not anywhere else.