From Bulbapedia, the community-driven Pokémon encyclopedia.
In Galar, Slowpoke's appearance is a result of particles being built from eating Galarica seeds. The main difference is that it has gained yellow markings on its forehead and tail.
Galarian Slowpoke are known to relax on seashores and riverbanks without a care in the world. Occasionally it will get a very sharp look in
their eyes as if it about to think of something tremendous. However at times Slowpoke will quickly forget and return to its normal expression. It is believed that its behavior is result of Galarica particles affecting its brain.<ref>https://swordshield.pokemon.com/en-us/expansionpass/pokemon/slowpoke/</ref>
==In the anime==