>Escavalier is probably based on the Drilus flavescens genus of beetle. Drilus larvae are known for eating snails and stealing their shells, explaining why it attacks Shelmet and takes the shell as a Karrablast

So essentially Karrablast steals Shelmet's armor and evolves to become more defensive, and Shelmet has to evolve into a more speedy creature to survive upon having his armor stolen. The dex also claims these two only evolve in the wild when they are near each-other.

What are some other cool Pokemon dynamics? Outside of obvious ones like Corsola and Toxapex and Yungoos and Ratatta.