When the control of this face-up card on the field shifts to your opponent, inflict 2000 points of damage to your opponent's Life Points. This effect can only be used once as long as this card remains face-up on the field.
Rulings
Individual Card FAQs
This card's effect is not activated when equipped to an opponent's "Relinquished" or "Thousand-Eyes Restrict".
If your opponent uses "Change of Heart" on a face-down "Ameba" and Flip Summons it, when it returns to you during the End Phase, its effect activates and you take 2000 damage.
Netrep Rulings
The effect of “Ameba” does not activate when control of “Ameba” changes while “Ameba” is face-down.