In the reboot movie.

If I’d met any Soong, I’d have made sure my dog lived forever. Immortal Porthos confirmed.

Archer was awful, yes. If his bullshit with Porthos didn’t directly contribute to the prime directive, it should have. But that wasn’t Porthos’ fault. Poor guy was just trying to boldly go, and he’d no idea those trees were sacred.

He also got the worst ending of nearly any character, with Scotty just misplacing him.

ENT is the best Star Trek because of Porthos. It’s not even a contest. Best character in any Trek, ever.