While other cards over the years have featured effects similar to this (mythic rare Zur, Eternal Schemer from Dominaria United comes to mind), Opalescence was the first to do it en masse for enchantments, and, due to its novelty and being first on the scene, it clocks in with a price point approaching $30
Features full-art Pokemon with unique backgrounds
I get it, Magic: The Gathering is great and has stood the test of time
Many of the cards from March of the Machine in this category are creatures that transform into other creatures
Just getting the Morbid trigger once is enough to feel good about things, and that's good -- but don't expect to make this go off one very turn
Hitmontop is on the bottom of the IR list despite its deck being harder to pull, likely due to its basic artwork