Impressionable Goo (Upped: Impressionable Sludge)
Cost: 4 (unspecified)
ATK|HP: 2 | 2 (Upped: 3 | 3)
Description: Absorb one quantum randomly from either side per turn. Gain that element's effect.
The element effects last one full turn, from attack phase to attack phase, and are the following:
Light: +2 damage against death or darkness mark
Darkness: Vampire
Air: Flying; +1|+1
Earth: +0|+3
Gravity: Momentum
Entropy: Either double or no damage (random...50/50, or maybe 60/40)
Fire: +2|-1 (Note: can kill if only one HP remaining; HP return to normal next turn)
Water: 20% chance to freeze (either weapon or creature if absorbed)
Life: Heal 1 HP at end of turn
Death: Deal 1 poison damage upon successful attack
Aether: Immortality
Time: See opponent's hand on successful attack (Alternative: 10% chance to deal neurotoxin)
Balanced? Interesting? I just love measured randomness, and think there needs to be more of it! With this card, you know what quantum you're going to have available to feed it, but not what your opponent will have, and it draws randomly from both.
One hitch: Sanctuary will prevent it from drawing quantum. I don't think this should be allowed to turn into a devourer (always stealing from your opponent), so I would say if sanctuary prevents it from absorbing quantum, then it just doesn't get an effect that turn (rather than only stealing from the side without Sanctuary).
ETA: If Goo doesn't appeal to you, perhaps the card could be a chameleon instead.