You become untargetable for 2 turns
Deal 2 damage to target creature (1 if airborne)
Perhaps: Obelisk : Target creature gains Dive [activation cost dependent on creature casting cost]
Obelisk : Heal 1hp per creature that died this turn.
Temporary stat bonus
Target creature is resummoned
Obelisk? : Return target pillar/pendulum/monolith to owners hand [not usable if hand is full]
? (fire probably) Your opponent loses Xhp. You lose Yhp.
Obelisk or Monolith? Draw a new hand.
Just like all.
For fire I realy like one that have something like :
1

: inflame : put a burning counter on fire obelisk. Generate 1+X

where X is te number of counter.
Could be balanced if needed