>>35227711The whole theme behind Pikipek's line is guns/cannons, which is why they have Skill Link as an available ability and use moves such as Rock Blast/Bullet Seed - most evidently seen in Trumbeak. It's a joke in Japanese wordplay in how the 'small gun' evolves into the 'big gun', derived from the names for woodpeckers and toucans.
And if you're still not buying it, its Pokedex classification is "Cannon Pokemon".
