FusionDex

Swampvanha causes silt and mud beneath lakes to quake, disrupting the ability for many aquatic Pokémon to see underwater. Once it creates this seismic activity, it darts through the slurry of mud to sink its teeth into a fresh meal.

Swampvanha attack ships in swarms, making them sink. If it senses the approach of a storm and a tidal wave, it protects its seaside nest by piling up boulders.