Slaking

Slaking boasts a fantastic Attack stat that puts even the Ubers metagame to shame. It has a good base 100 Speed stat too, allowing it to outspeed some key threats and force them out with its strong attacks. Unfortunately, Slaking's amazing power can only be tapped into every other turn due to its ability, Truant. Thus, Slaking has to rely heavily on proper predictions to punch through teams most effectively and is forced to use a Choice Band set, seeing how it's almost always forced to switch out after firing off just a single devastating attack regardless of its effectiveness. The opportunity cost of adding Slaking to a team is also extremely large, as it allows dangerous sweepers to come in for free every other turn. Moreover, due to how important role compression and momentum is in Ubers, you're often hard pressed to fit Slaking outside of extremely specific builds, and even then it's hard to justify the team slot it occupies.