Thrýlos, Immolation Mage

Haste
Whenever an enchantment enters the battlefield
under your control, add {r} to your mana pool.
Until end of turn, you don't lose this mana as
steps and phases end.
Whenever Thrylos, Immolation Shaman attacks,
you may pay any amount of {r}. Thrylos gets
+1/+0 for every {r} you payed.