T-3000, "John Connor"

Whenever T-3000, "John Connor" attacks,
you may cast an artifact spell from your hand
or graveyard by paying life equal to its mana value
rather than paying its mana cost.

"At the end of the war, Skynet was trying to develop
a new type of infiltration unit by infecting human subjects with machine-phase matter. It restructures
and rebuilds human tissue on a cellular level for
maximum combat utility."
[Anrakyr the Traveller]