Tengu format ruling
Swap Frog
Card effect (current official text)You can Special Summon this card (from your hand) by discarding 1 other WATER monster. When this card is Summoned: You can send 1 Level 2 or lower WATER Aqua monster from your Deck or face-up field to the GY. Once per turn: You can return 1 monster you control to the hand; you can Normal Summon 1 "Frog" monster during your Main Phase this turn, except "Swap Frog", in addition to your Normal Summon/Set. (You can only gain this effect once per turn.)
Rulings
- Discarding 1 WATER monster for this card’s Ⓢ is a cost. This does not start a chain.
- You can only use the ② effect once per turn while Swap is face-up. (If Swap leaves the field, and is then resummoned that turn, it can be activated again).
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Tengu forum — sourced change requests get reviewed.