play for an animal is doing things they need to know how to do (ie, fighting, running etc) when they dont' need to do it. Play is any normal activity, practiced outside of when it's needed.
For example, a killer whale will grab a seal, release it and hunt it-whereas they could have just eaten it-no need right? But that's play.
For rabbits they play by running jumping and hiding-as a prey animal-evasion of predators when no predators exist-is play.
Growling, pouncing, biting,chasing and running -for a predator is play. It's highly unlikely what your pup was doing was anything other then normal puppy play.
I agree-the biting and growling can sound scary. My dog sounds like a determined rottweiler at prey when he's playing-but he's just playing.
A video would be great-but I guarantee you-your pup is playing