mtg phyrexian cards Horror Green function toggle Phyrexian Negator from Urza's Destiny

Until your next turn, instant, sorcery, and planeswalker spells that player casts cost less to cast

If Thancred Waters leaves the battlefield or you lose control of it before its triggered ability resolves, the target legendary permanent won't gain indestructible at all

I am the storm. 2/3 Illustrated by Ryan Alexander Lee Standard Not Legal Alchemy Not Legal Pioneer Legal Historic Legal Modern Legal Brawl Legal Legacy Legal Comp

Wizards of the Coast has said that proxy cards are not allowed in competitive play such as sanctioned tournaments

Or, it could be an ongoing scheme, in which case it remains on the field until an ability causes you to abandon it