Remoraid = Remora + Raid. Based on an archerfish.
Octillery = Octopus + Artillery. Based on artillery.

Both of which are able to learn a number of beam-based attacks, which are pretty much representing the ranged factor of the weapons/animals they're based off of.

How many of these (possibly genwunner) posts are gonna crop up? _;

Wasn't this answered so many times already?
It didn't took me that long to figure out why they evolve like that. Its beam-like moves (even move like flamethrower) and its name were pretty obvious to me. Even one of his abilities is Sniper. I always saw Remoraid as a gun and Octillery as a turret.