Flash Thompson, Spider-Fan

Flash on a two-drop is the tell. This is a creature built to be held with mana up and dropped into a combat or targeting window nothing else can occupy, and the enter trigger is what it does when it gets there: a tap or an untap, or both at once. Read one way it is a Falter effect, tapping down a blocker so an attack lands; read the other way it is a combat trick that untaps your own creature for a surprise block or a second use of a tap ability. The "one or both" clause is what stretches the card past a single-purpose trick, because both modes at instant speed means you can strand an opposing attacker while readying your own tapped defender in the same flash-in, all off a body that still trades in combat afterward. Most white two-drops that manipulate tap state ask you to commit at sorcery speed or pin the effect to attacking; putting it on a Flash creature turns a modest utility line into a reactive one, answerable to what the opponent actually does rather than what you guessed on your turn. The Spider-Fan framing dresses up a genuinely tight little control piece: cheap, evasive in its timing if not its stats, and doing the most work in the moments a normal white creature would already be committed.