Mournwillow

Delirium as an enters-the-battlefield trigger is the wrinkle here. Most graveyard-payoffs of this lineage hand you a static buff or a recursion engine the moment you hit four card types; this one cashes the threshold for an evasion clause that fires only when the creature enters, and only that turn. Haste is what makes that window matter: a body arriving the turn you cast it, swinging immediately, with small blockers told to stand down, is a one-shot push of three damage past a clogged board. Skip the threshold and you still have a serviceable haste creature, just one that any 2/2 walls without ceremony. That conditional is the whole balancing act: the floor is a fragile 3/2 beater in green-black, the ceiling is a guaranteed connection, and the difference is entirely how stocked your graveyard is when it lands. It rewards the kind of self-mill and cheap-spell churn that delirium decks already want to do, then converts that work into reach rather than card advantage. The narrow band of blockers it punishes (power 2 or less) is the design discipline: it does not blank a real defender, only the chaff that aggressive boards tend to run into in the midgame, so it functions as a tempo finisher rather than a way to muscle through anything substantial.