Urza's Mine

{T}: Add {C}. If you control an Urza's Power-Plant and an Urza's Tower, add {C}{C} instead.

Urza's Tower

{T}: Add {C}. If you control an Urza's Mine and an Urza's Power-Plant, add {C}{C}{C} instead.

Urza's Power Plant

{T}: Add {C}. If you control an Urza's Mine and an Urza's Tower, add {C}{C} instead.

Nullhide Ferox

Hexproof
You can't cast noncreature spells.
{2}: This creature loses all abilities until end of turn. Any player may activate this ability.
If a spell or ability an opponent controls causes you to discard this card, put it onto the battlefield instead of putting it into your graveyard.