Pokémon X and Pokémon Y

I didn't know it was possible until today, but I found a wild Pokemon that already knows the HM move "Cut." :f6:

Since when was this a thing? Can you catch Pokemon that know things like Surf, Whirlpool, Fly, and so on?

Goldeen and Seaking have learned Waterfall via level-up since Gen 1 (though it wasn't an HM until Gen 2).

Salamence and Rayquaza have learned Fly through level-up since they were introduced in Gen 3.

That said, nothing learns Cut through level-up. What Pokemon was it, and did it use it during the battle?