Advanced format ruling
The Last Warrior from Another Planet
Card effect (current official text)"Zombyra the Dark" + "Maryokutai"
If this card is Special Summoned: Destroy all other monsters you control. Neither player can Summon monsters.
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.