Reactor Core

{t}: Add {c}.

At end of turn, put a power counter on Reactor
Core. Whenever Reactor Core is tapped for mana, add an additional {c} for every power counter on Reactor Core.

When Reactor Core enters the graveyard with at least six power counters on it, each player sacrifices three creatures and three lands, then every player adds {e}{e}{e}{e}{e}{e}.