Lamponoaa

After leeching off 50 separate hosts, Preypetra evolves into Lamponoaa. With all the gathered DNA, its body develops a jaw that isn't really a jaw. Stone plates calcify onto its head, giving it a skull, but its "jaw" is actually still its rocky mouth from before that sucks things in. The skull has several extremely sharp spikes that can pierce through thick skin. The stone plates on its back now no longer stick onto hosts, instead turning into rocky spikes. Lamponoaa intentionally slams into Pokémon with its back to impale them with those spikes. Lamponoaa can be found in lakes, but it's typically found on the coast, where there are constant efforts to isolate and contain this rogue Pokémon. The currents of its mouth are indeed enough to suck in a person without much effort. They aren't particularly hard to find, considering that they produce sounds with frequencies so high they can reach other continents.