Lets break down how thickness works and how it relates to GSM
Its a fantastic way to remove some combo pieces or deck-defining cards in basically any format, and its cheap enough to be played
When you don't need to consider dipping into green for artifact destruction or black to get rid of a creature forever, it goes a long way
Most Worm Decks use Worm Xex and Worm Yagan in conjunction with Offering to the Snake Deity to control the field
In each 12-card booster, you'll find: 1 Mystical Archive card (uncommon, rare, or mythic rare) 1 Lesson card of any rarity 1 Traditional foil card of any rarity* 1 Card from The List in 1 out of 4 boosters (*This includes global Mystical Archive cards in all non-Japanese Set Boosters, and both global and Japanese alternate-art Mystical Archive cards in Japanese Set Boosters.) Plus, you get a delightful art card, 1 in 20 of which feature a foil-stamped logo or artist signature
There's no guarantee that you'll have a second target, but in a color combination that's often starved for cards, getting as much value out of each spell is paramount