Thunderblust

Creature - Elemental 7/2, 2RRR (5)
Haste
Thunderblust has trample as long as it has a -1/-1 counter on it.
Persist (When this creature is put into a graveyard from the battlefield, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)¹
Illus. Dan Scott

Gatherer Card Rulings [Nov 2009]

• 8/1/2008: Whether an attacking creature has trample matters only at the time you assign combat damage. If Thunderblust loses its -1/-1 counters before combat damage resolves, it will no longer have trample, but the damage will still be dealt as assigned.

Format Legality	Legal in Vintage, Legacy, Extended Banned in Standard
Printings (1/9)	Eventide (Rare)