Advanced format ruling
Mass Hypnosis
Card effect (current official text)Activate only while you control an "Alien" monster. Select and take control of up to 3 of your opponent's monsters that each have an A-Counter(s) on them. This card is destroyed during the End Phase of the turn it is activated.
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.