Experiment Rex

Kicker {4} (You may pay an additional {4} as you
cast this spell)
Deathtouch, Indestructible, Trample
If you didn't pay the kicker then this creature
loses Deathtouch and Indestructible and -3/-7.
{t}: All creatures you control are indestructible
until end of turn. Summon this as an instant.