Flamefang, Dragon of Imrryr

Flash, flying, deathtouch
Flamefang, Dragon of Imrryr doesn't untap
during it's owners untap step.
Whenever Flamefang attacks or blocks,
you may pay {x}{r}. If you do, Flamefang
deals X damage to any target and gets
+1/+0 until end of turn.
{2}{b/r}: Untap Flamefang.