Xantid Swarm

Combo decks have always feared the same thing: the open mana on the other side of the table, the held-up counter that turns a winning turn into a dead one. This 0/1 answers that fear for a single green pip and a swing. Once it attacks, the defending player is locked out of casting anything until the turn ends, which means a combo player can untap, send the bug in, and then go off with no risk of interaction on their own turn. The elegant wrinkle is that the lockout fires on the attack trigger itself, not on combat damage; whether it gets blocked or even connects is beside the point. Flying simply means there are fewer creatures that can profitably block a 0/1, but the card does not need to push through anything to do its job. You are not racing or pressuring life totals; you are buying a single uninterruptible window and paying almost nothing for it. The cost of that window is paid by the body, which does nothing else: it cannot threaten a clock, and against a deck that does not interact on your turn it is a blank. Green rarely gets to police the stack, and it does not get to here either; what it gets instead is the ability to deny the stack to someone else for one crucial turn. The design is narrow on purpose, combo insurance dressed up as a one-mana flier.