Illusory Demon

Four power of evasive beater for three mana looks like a deal until you read the cost: this creature folds the moment you cast anything else. The aggressive stat line is paid for not by a mana premium but by a behavioral lock, and that lock reframes how you build around it. Every spell in your hand becomes a liability the turn after this lands, so the deck that wants the body has to be one that can sit and hold removal, counters, and tricks rather than deploying them. The design idea is a tempo creature that punishes its own controller for reactivity: you get a fast clock, but only if you commit to doing nothing but attacking. It pairs awkwardly with the very instant-speed interaction blue and black usually want to hold up, which is the real friction here. The Illusion subtype is the flavor key, a phantom that exists only as long as you give it your undivided attention; the moment you reach for another card, it dissolves. As a piece of aggressive-tempo design it rewards a stripped-down, creature-light shell where the four-power flier is one of your only ways to spend mana, and it asks you to treat your remaining spells as resources to dump before it arrives rather than after.