Tengu format ruling
The Big Saturn
Card effect (current official text)Cannot be Special Summoned from the hand or Deck. Once per turn: You can discard 1 card and pay 1000 Life Points; this card gains 1000 ATK until the End Phase. When this card in your possession is destroyed by your opponent's card effect and sent to your Graveyard: Both players take damage equal to this card's ATK in the Graveyard.
Rulings
Discard 1 card and paying 1000 Life Points are a cost.
If "The Big Saturn" is destroyed by your opponent while equipped to "Relinquished" its effect still activates.
The effect of "The Big Saturn" to inflict damage only activates while the owner of the card controls it.
The damage dealt is the original ATK of "The Big Saturn".
If "The Big Saturn" is destroyed while it's in your hand, the effect to deal damage still activates.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Tengu forum — sourced change requests get reviewed.