The best Pokémon evolution is tardigrade -> axolotl -> capybara.
@Pat In this series of games, players collect various imaginary animals. An animal can be "evolved" to more powerful form.
More information than you require:
@peterdrake Quite the logarithmic size increase! Also, water type -> water type -> water/ground type?
@peterdrake
I don't know what Pokémon evolution is, but those are three really cool species.