For many collectors, the Galarian Gallery is the single best thing to come out of the Sword and Shield era, and Crown Zenith concentrated an enormous number of these cards into one chase-able set
Each card in a series has a collection number, usually located in the bottom left or right corner of the card
Muk has two moves, the first one is called Strange Poison, this move requires two energy cards, one Psychic and one colorless, it does 30 hp damage and when you use this move you are to flip a coin if it is heads, the defending Pokemon is poisoned, if it is tails Muk is poisoned
Both are spider-like beings that turn their environment into crystal
This pair is obviously great in kindred creature type matters brews which are pretty common at kitchen table formats and play from Simic Elves to Mono-Blue or Azorius Merfolk to Wizards to all color Slivers