Here is Blast here is his theme music [link] He is Sonic's pride and joy and he is the Fastest Thing Alive and he is mainly a showoff kind of like Sonic but he is a good guy and helps people anytime & anywhere.
Most likely from some pony generator. You forgot to credit it. And like most mlp oc it has to have something over powered with it, for example "He's the fastest thing alive". And seriously sonic and rd getting busy together thanks for putting that in my head.
Even if a pony and a hedgehog WERE somehow able to conceive, the resulting offspring would either die shortly after birth, bear significant physical deformities, or, at the very least, be completely sterile, and unable to produce offspring of its own.