Also happens with safes, carrot juice cans or anchors, depending on the level you're in. Anvils' shadows appear occasionally, and stepping on them obviously prompts them to fall.
Making Bugs doing a Double Take at the horse wearing Merlin's hat nonsensical. Neither does Bugs turn Merlin into a horse in retaliation for turning him into a pig, as Merlin snaps his fingers instead of using magic powder. Adaptation-Induced Plot Hole: The final cut-scene from getting 100% Completion adapts the ending Knight-mare Hare with Bugs thinking his adventure was All Just a Dream, when it was clearly not the case.Adaptational Heroism: In his debut cartoon, Merlin is jerk who messes with Bugs for no real reason, but here, while a bit mischievous, he's amazingly selfless and really goes out of his way to help Bugs.