Advanced format ruling
Jam Breeding Machine
Card effect (current official text)During each of your Standby Phases: Special Summon 1 "Slime Token" (Aqua-Type/WATER/LEVEL 1/ATK 500/DEF 500) in Attack Position. You cannot Summon any monsters, except "Slime Tokens" (but you can Set).
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.