Elements has several examples of this type, mostly in the Entropy element: Mutation causes the the target creature to die, turn into a mutant, or turn into a different, random creature with a random power
Atraxas Fall combines both of these worlds into a very cost efficient 2 mana spell
His other ability came from a weird place
Cresselia is a Psychic Pokemon that allows you to fully power up a stronger Pokemon if you manage to play it on the first turn (giving you the chance to grab three Psychic Energy cards from your deck and attach them all to one of your Pokemon)
Check out these powerful cards below, each with a sample deck to maximize their potential
How to Apply this to Your Own Decks In going through this exercise, there were a handful of takeaways I came across that Id recommend when optimizing your deck for the Upgraded Bracket (3): Choose your Game Changers I dont think every Upgraded deck must run three Game Changers, but I think its a resource available to us in this bracket and will clearly define a decks power level