Who's That Pokémon? (1)

I'm going to describe a Pokémon, you guys guess!

It has long tentacles and a beak-ish thing. It's based off a squid, I think. Anyways, it has beautiful, mesmerizing flashing lights that you just can't take your eyes off! It can Mega Evolutionize, making the lights prettier and giving it a bigger brain. It's strong, smart, and just flat-out amazing! Everyone loves it (except Voltareon, but they will in time!)! Most importantly of all; it is your bestest friend!

Who's that AMAZING Pokémon?