For other's it about imposing your will on the game, whether it be controlling the board state via mass destruction, pinpoint removal spells, or (heaven forbid) mana denial/destruction
If a creature is dealt damage equal to or greater than its toughness over the course of a single turn (whether it be combat damage, damage from spells or abilities, or a combination of both), that creature is destroyed, and it goes to its owners graveyard (or "dies")
These cards dont exactly matter for card advantage except in one specific corner case, which well get to in the next section
In truth, Muk is a bit too hard to set up regularly
It takes a lot of mana to make the removal side work, but if you manage to get delirium, it doesnt really matter as it doubles the damage of your burn spells, as well as pingers like Thermo-Alchemist