This is called the "black core" layer
I freely admit I skipped this, between my buying up Dragonscale fetches and saving for assorted Final Fantasy goodies
Marvel Cosmic Invasion : Rocket Racoon's Cosmic Grenade ability has him throw a bomb that explodes with a random effect- it may simply deal damage, cause a glue bomb that slows enemies, inflict Cosmic damage over time, or there's a very very low chance of getting a Nuclear Grenade that causes massive damage to all enemies on screen
MONUMENT TO ENDURANCE Monument to Endurance is a busted little engine card that has proven its worth in both Standard and Commander
This is because Limited is full of creatures, and the removal that exists tends to be clunky (even good ones like Sephiroth's Intervention cost 4 mana)
I mean, the most popular death metal band of all time, "Cannibal Corpse" is a direct reference to a Zombie