budget yugioh decks.com all meta decks The Best Decks in Yu-Gi-Oh! Master Duel 3 Competitive Budget Decks You

It's less commonly used as an activated ability, like on Doorkeeper which lets you pay two generic and a blue to mill someone for as many cards as creatures with defender you control

They can just be two or more cards that are more powerful when played together

You need colorless mana (of course) to activate the ability, and your creature comes back tapped, but its certainly a valid option

However, the potential afforded by this card is so stupidly strong that all Water decks need to have it at their disposal: if you get lucky, your Water types at looking at three, four, five, or even six Energy

Cast it without paying its mana cost