Nebula, Enhanced Rival

Artifacts you control have "Sacrifice this artifact:
You gain life equal to its mana value".

Whenever you sacrifice an artifact, Nebula,
Enhanced Rival gains indestructible until end of
turn.

At the beginning of your upkeep, if Nebula is in
your graveyard, you may pay 3 life and sacrifice an artifact. If you do return Nebula to the battlefield
tapped.