FusionDex

Polinix keep young Poliwag safe within the bubbles in their body, providing them shelter from predators. They rear up and use powerful Slams to knock away other large Pokémon if they feel they're a threat to their young charges.

There is a magnet in its brain that prevents an Polinix from losing direction while tunneling. It is possible to see this Pokémon's spiral innards right through its thin skin.