Raichu

Raichu carves out a niche for itself in OU as the only fully evolved Electric-type with access to Water-type coverage; this lets it almost always OHKO Rhydon and Golem, which other Electric-types, such as Jolteon and Zapdos, are walled by. Raichu can use its unique coverage to force paralysis past usual paralysis absorbers, such as Starmie and Chansey, and onto foes that will usually attempt to avoid paralysis, such as Exeggutor and Alakazam.

However, Raichu is 3HKOed at best by most physical attacks and loses one-on-one to nearly every physical attacker. It also gives free entry to Grass-types, such as Victreebel and Exeggutor, and is effectively forced stay in and absorb Sleep Powder. It competes with Jolteon and Zapdos, which, aside from lacking Surf, are better in almost every way. Raichu is able to perform as a decent mixed attacker, but it is too frail, too vulnerable to status, and too weak to make up for it in the vast majority of situations.