Porygon2

Porygon2 is a quirky Pokemon, both aesthetically and competitively. The bizarre Internet duck is one of the most versatile Pokemon available. Two great abilities, Trace and Download, allow it to become a good tailor-made counter to just about any bothersome Pokemon your team may be having trouble with. Not only that, but it also has an expansive movepool, good defenses, and a decent Special Attack stat. However, Porygon2's Speed is troubling, and its Normal typing, without a giant HP and Special Defense stat to back it up like Chansey has, is just OK defensively. Also, if you tailor Porygon2 to counter a specific threat and your opponent doesn't even have that Pokemon on their team, then it essentially becomes dead weight. Porygon2 can really mess with teams in the right hands, but most times it will be too specialized to warrant a team slot, especially when there are better general answers to UU's top threats.