I also want to point out that this creature does not , in fact, have only the one horn
Both sides of the MDFC work well together
The examples given by Magic lead designer Mark Rosewater are Muscle Sliver, Cloudgoat Ranger, and Pact of Negation
Same thing with having a Fezandipiti ex [Shrouded Fable] and Latias ex [Surging Sparks] on the bench, we have the space now
Make sure to look up the rules so you know youre in compliance when going to a competition
As these examples show, the complexity of paying an alternative cost can range from very simple (pretty much like casting the creature normally from your hand, like when evoking, warping, or overloading), to requiring a bit of work (like flashback requiring the spell to be in your graveyard), to demanding very precise timing (such as madness)