Spell in your Deck, usually the Field Spell, P.U.N.K
As a reminder, this can also be a tricky upgrade for Changeling decks since most of your creatures will trigger Freerunning
P(Not In Hand) The probability of not being in hand is relatively simple to calculate when there is only one copy in deck
Certain spells in Magic have a unique keyword called suspend, which acts as an alternate casting cost, often times cheaper than its regular one, at the expense of having to wait a few extra turns to finish casting it
It's strong in ETB heavy brews like midrange and blink, sacrifice brews where you can sacrifice to something like Attrition and then come back, Aristocrats where you can trigger Blood Artist for wins, life gain for lifelink shenanigans, Voltron and equipment that invested in equipment infrastructure to and any heavy creature build
In the case of He-Man, it was action figures