Parasect

Type Tier
Bug / Grass UU
Statistics
Stat
HP
60
323
Atk
95
288
Def
80
258
SpA
60
218
SpD
80
258
Spe
30
158
Name Item

"Doublepowder"

Leftovers
Moveset
~ Spore
~ Hidden Power Bug
~ Giga Drain
~ Stun Spore

OK, for this, you have to switch into something that won't kill Parasect after one hit, or two hits if you plan on getting hit on the switch. Spore whatever Pokémon, and this is where Parasect's usefulness pretty much ends. Use Stun Spore to paralyze whatever comes in next. After this, just attack away. If you used Stun Spore, you should have the Speed advantage, so enjoy that while it lasts. Giga Drain can dent Rhydon / Quagsire / Golem, if they decide to switch in.

Name Item

Special Sweeper

Leftovers
Moveset
~ Spore
~ Growth
~ Giga Drain
~ Hidden Power Fire / Hidden Power Ice

Good luck staying alive long enough to set this up. Spore might be able to buy you a free turn or two, and maybe they'll bring in a Steel-type expecting physical Parasect. Hidden Power Fire covers Steels and Bugs, whereas Ice covers Fliers (especially Dragonite, should you use Parasect in OU). Both hit enemy Grass-types. You could use Hidden Power Rock for the inevitable Fire-type switch in. Hidden Power Rock is a better choice than the special Hidden Power Fire because you will not be hitting them after using a Growth (when you use Growth, they just switched in, are faster than you, and OHKO), meaning you'll have to whittle them down on switches. With Hidden Power Rock, you can use Parasect's superior Attack stat. This also lets you hit Flying-types on the switch. The only advantage of Hidden Power Water is if you have paralysis support, or are using Parasect in OU for some reason and need to hit Steelix harder.

Name Item

SDer

Leftovers
Moveset
~ Spore
~ Hidden Power Bug
~ Return / Sludge Bomb
~ Swords Dance

This Parasect attempts to sweep with Swords Dance. It will usually be about as useful as the first set (put something to sleep with Spore). Losing Stun Spore means you have less of a guarantee of long-lasting damage, though, so it's a bit riskier.

Other Options

It has access to Reflect / Light Screen and can actually pseudo-pass just as well as anyone else. Thief is actually a good choice with Parasect's sparse movepool. You might want to consider Stun Spore + Spore + Thief + Reflect / Light Screen as an all-out support Parasect.

Opinion

Argh. This thing is probably one of the 5 worst fully-evolved Pokémon in the game. Definitely bottom 10. Very cool, however, and with Spore / Stun Spore, can cause a few status ailments for support.

Counters

Parasect has the unfortunate trait of being both extremely slow and weak to many types of attacks. Sleep is not nearly as valuable in GSC as it is in other generations, and the variety of Pokémon with Sleep Talk detracts from the only advantage Parasect has in Spore. Parasect is quadruply weak to Flying and Fire attacks, so something like Arcanine or Fearow will easily OHKO. Also not helpful are Parasect's Rock and Ice weaknesses. Additionally, Parasect isn't a very strong attacker either, so basically anything that resists Hidden Power Bug beats it. Basically, any decent team can handle Parasect.