The Rainbooms are a hit band from CHS and have since been recognized by Canterlot City not just from their songs, but also talent.
Spike Sparkle, feeling left behind from the girls friendship tries to be included, but is constantly overlooked and after being rejected once more, decides to sing a song that fits him and what he is going through
Only he may actually show his talent in the way he never expected.
Everything belongs to rightful owners.
(PS: This universe is where Spike is human and there is no magic related issues and there is no actual sex but the song Poison from Hazbin Hotel is mostly sexual. That is why the Sex tag is there.)
Inspired by the fanfic
Equestria Girls: Dragon Rocks - Fimfiction
Not technically a crossover with Hazbin Hotel, but the song Spike will sing is technically from it.