Metathran Exile

Whenever Metathran Exile attacks, you may pay {u}. If you do, Metathran Exile can't be blocked until end of turn.
Whenever Metathran Exile attacks, you may pay {r}. If you do, Metathran Exile deals 1 damage to target creature.
Though many of Urza's genetic soldiers did not survive long after the Phyrexian Invasion, a few Metathran escaped to other, far off worlds."