Advanced format ruling
Ameba
Card effect (current official text)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.
Current rulings for this card are maintained by Konami.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Advanced forum — sourced change requests get reviewed.