Koopa Troopas are pretty intense villains from the Mario series and they were once known as fierce opponents! They may not command the same respect and recognition that they used too, but I definitely wouldn’t want to have to go up against one of them without a trusty Squirtle. Squirtle is a good match against a Koopa because his water abilities can nullify all of Koopa’s attacks. Koopa won’t be landing any hits on the mighty aqua fighter and Squirtle can end this with a solid headbut. Squirtle wins.