How does a gladiator beast card get sent to the graveyard?

It says, "At the end of the battle phase, if this card attacked or was attacked, you can return it to the deck to special summon 1 "gladiator beast" monster from your deck" So how does this card not get sent to the deck, but to the graveyard?|||A glaiator MUST survive in battle to go back to the deck, thats why people use waboku, book of moon, shrink and such|||the glad beast that attacks or is attacked must be able to survive the battle eg. by using waboku