Goat format ruling
Monster Reborn

Card effect (current official text)Target 1 monster in either GY; Special Summon it.
Rulings
- If "Monster Reborn" or another Spell Card that can Special Summon a monster was activated with all 5 of the Monster Zone spaces already filled, would that be considered an illegal activation or does it simply resolve without effect? A: It would only be an illegal activation if 5 monsters existed on their side of the field when Monster Reborn was activated.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Goat forum — sourced change requests get reviewed.