Artifact
Double Masters
50/100
Plays about the same in 2HG as it does in any other format.
No 2HG-specific rules fire on this card — it plays much the same here as anywhere else.
Ratings start at a neutral 50 and are adjusted by rules derived from 2HG's structure — shared 60 life, shared turns, two opponents. They'll be recalibrated against real play rates once teams start submitting decklists.
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.)