Inner Demon

The board sweep is the part that should not be on an Aura. Most pump enchantments do one narrow thing: they commit a creature and a card to make a single attacker bigger, and they leave the rest of the table untouched. This one folds a -2/-2 sweep into the enchant trigger, and the sweep is symmetrical, hitting every non-Demon in play, which means the design has to keep its own target intact. The retyping does that work: the enchanted creature becomes a Demon before the -2/-2 resolves, so it holds the +2/+2 for the turn rather than shrinking with everything else. Even a non-Demon target would survive its own sweep, since the +2/+2 cancels the -2/-2 to net back to base toughness; the Demon type is what preserves the buff instead of washing it out. Everything else you control that is not a Demon still gets caught in the same net, so the card wants a target you have already committed to and a board you are willing to sacrifice around it. The entering trigger therefore pulls double duty: it clears the opponent's small creatures and hands you a flier that has already outgrown the sweep. The sweep fires on entry, so it repeats whenever the Aura re-enters, whether cast fresh, blinked, or recurred; and the whole package still answers to a single enchantment-removal spell or a bounce that carries the creature off with it. It reads less like a combat trick than a removal spell that happens to leave a body behind.