[LockonStratos]

Almost every Pokémon can have Toxic. It's one of the most common moves in the game.

Houndoom's ATK isn't crap, but if you really want to poison something with it, which is not a good idea considering its poor defenses and the fact that just going for the knockout is a better call for it's statlines, Sludge Bomb would serve your purposes better. Sure, it's normal poison, but any fight involving a Houndoom isn't going to last long enough for badly poisoned to pay off, as either you'll knock the target out first or you will be KO'd yourself.