Trinisphere
Artifact
As long as this artifact is untapped, each spell that would cost less than three mana to cast costs three mana to cast. (Additional mana in the cost may be paid with any color of mana or colorless mana. For example, a spell that would cost 
to cast costs 
to cast instead.)
"This exhibition of Nehra's Threshold Principle must be expropriated and examined for its potential applications in enforcement." —Confiscation directive
Commander bracket
Derived from card traits, not a ruling — bracket rules turn on how a deck intends to use a card. Bracket rules
EDHREC
Combos
Not part of any combo on Commander Spellbook.
Format legality
Rulings
- 2020-08-07
If Trinisphere leaves the battlefield or becomes tapped or untapped as a cost to cast a spell, this cost is paid after you've locked in the total cost.
- 2020-08-07
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying, add any cost increases, then apply any cost reductions. Finally, apply Trinisphere's effect if the mana component of the spell's cost is less than three mana. The mana value of the spell remains unchanged, no matter what the total cost to cast it was.