Tevaris, Thorn's Scabbard

Whenever Tevaris attacks or blocks, you
lose 2 life and create Blackthorn, a legendary
black 3/3 Insect creature token with double
strike and "When this creature dies,
sacrifice Tevaris." If it's your turn, it enters
the battlefield tapped and attacking.
Otherwise, it blocks this turn if able. Exile
it at end of combat.