Parasect

Parasect is certainly an interesting and unique Pokemon. His odd typing grants him extremely useful resistances to Water-, Ground-, Grass-, Fighting-, and Electric-type attacks, and his defenses are decent enough to utilize these resistances effectively. His excellent ability, Dry Skin, allows him to switch into bulky Water-types with ease, and also slightly heals him at the end of every turn while in the rain, giving Parasect a unique niche on Rain Dance teams. However, none of the aforementioned factors are Parasect's main selling point. Parasect's most useful trait, by far, is his access to Spore, which gives him the ability to cripple any counter temporarily, almost always allowing Parasect to damage the opposing team in some way. All of these unique characteristics make Parasect stand out amongst both his Bug- and Grass-type brethren, giving him competitive value and usability.

Unfortunately, it isn't all good news for Parasect. Parasect's typing grants him horrible, crippling weaknesses to Fire-, Flying-, Poison-, Rock-, Ice-, and Bug-type attacks, most of which are common in the UU metagame. Parasect is also exceedingly slow, and is outsped by almost every Pokemon in the UU tier, except for Slowbro and Steelix (whom he speed-ties with). Due to these two traits, it's extremely easy to hit Parasect with a strong super effective attack once he switches in. In conclusion, Parasect, despite his many faults, can prove fairly useful to a team thanks to his unique assets.