When it's defeated, exile it, then cast it transformed.) When Invasion of Arcavios enters the battlefield, search your library, graveyard, and/or outside the game for an instant or sorcery card you own, reveal it, and put it into your hand
More importantly, this is a great introduction to Ruby/Sapphire's focus on Item cards, which set 7 Legendary cards in Lorcana emphasize through the new Tamatoa and Scrooge McDuck
Four and five were often easy targets and hard to design top-end cards for, so seven felt natural, and the reference worked
Invasion of Shandalar B-Tier: Invasion of Shandalar looks like one of the most fun battles
but if you are playing Amethyst/Ruby Control, you could include Jim Hawkins - Space Pirate in your deck, use him to play it for free and immediately have a character there ready to draw you an extra card next turn
And it works well with flashback