Hector the Reflector
Hector the Reflector is the third boss of Yoshi's Island DS. Hector the Reflector gets his name from the mirror part of the battle: he is reflected in the mirror, but cannot be seen anywhere else. It could also be a reference to the nursery rhyme, "Hector the Protector."
Hector is a Boo-like ghost 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 uses both screens. 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 them for more eggs.
After six hits, he vanishes, granting Yoshi access to the next level.
Names in other languages