Defense Grid
Artifact
Each spell costs 
more to cast except during its controller's turn.
"Properly installed, each powerstone emits a targeted electromagnetic field that halts momentum as sure as stone." —*Tome of Obstructions*
Mark Tedin
Rulings
In Two-Headed Giant, spells don't cost extra on your own turn.
(wotc • 2006-05-01)
The additional cost can be reduced by effects that reduce costs, such as Sapphire Medallion.
(wotc • 2004-10-04)
Rulings
In Two-Headed Giant, spells don't cost extra on your own turn.
(wotc • 2006-05-01)
The additional cost can be reduced by effects that reduce costs, such as Sapphire Medallion.
(wotc • 2004-10-04)