chimera card sleeves Sleeve Kings: Standard USA (57.5x89mm) while others have a solid colour Mayday USA MINI Chimera Deluxe

Additionally, it has a cool interaction that allows you to cast it for only 6 mana most of the time via madness

Check out the awesome action and dynamic duos in the Sun & MoonTeam Up expansion

Generally speaking, Magical Stone Excavation is a bad card because you're trading 3 cards (itself, and the two you discard) for just 1 card back, costing you 2 cards in the process, although this isn't true for all cards since the card One for One (quite ironically, a 2 for 1) will always generate advantage, despite technically always costing you a card since you could potentially summon something like Glow-Up Bulb which can recur from the grave at no cost your hand or field, effectively replacing the card you discarded for One for One while also (going back to point 1) progressing your gamestate by helping you make easy Synchros

For Cats, we already have Arahbo, Roar of the World, and while it's a great commander, Arahbo more supports a Go Tall strategy whereas a lot of the best Cat Tribal cards promote Go Wide (Feline Sovereign), which Rin and Seri support better