Muldrotha is in Sultai (black/green/blue) colors, giving you access to easy ramp, counterspells, and removal
If you are building decks with the cards you own, you will want to organize your collection in such a way that you can readily find the cards you have that do particular things
With that encore ability, you'd think the best play is to get Broodmate Tyrant into your Graveyard as fast as possible, but an even better plan is to cast it normally
The thing I love about this card is how incredibly unfair it is
The card, which sports the serial number #1, was opened by major seller Star City Games, and auctioned over Twitter by the store's general manager of sales, Ben Bleiweiss