Level 50 Statistics (see level 5, 50, 100)
With the right circumstances, Oddish can be one of the best sweepers under the sun (pun intended). While Oddish has subpar stats compared to many of the other sweepers in Little Cup, it does have something going for it: Chlorophyll. Sunny Day lets Oddish outpace most of the Little Cup metagame, and gives it a great STAB option in Solarbeam. While Bellsprout may do a better job of sweeping in the sun, Oddish is certainly capable of it, and should not be overlooked.
This set focuses on Oddish's overall good defenses, very high Special Attack, and very good Speed with Sunny Day up. Typically seen playing a support role on a Sunny Day team, this set also packs a punch, capable of busting holes in the opponent's team and making it easier for other sweepers to plow through the rest of the team.
Sleep Powder is an excellent support move as it can cripple potential counters to Sunny Day teams, such as Munchlax or Snover. Sunny Day is a fairly self explanatory move, helping out Oddish as well as the rest of the team. SolarBeam hits very hard with 120 Base Power backed by STAB and a Special Attack stat of 18. Synthesis is an excellent move with Sunny Day up and a bulky EV spread because Oddish will be able to restore two-thirds of its health in one turn, making it tough to take down if you don't pack a super effective move.
Team Options & Additional Comments >>>
If you were to use Oddish as a regular sweeper without Sunny Day, you would undoubtedly be underwhelmed by its very low Speed (and low stats in general). However, with Sunny Day up, Oddish becomes a very dangerous threat. Chlorophyll makes up for Oddish's lack of Speed by doubling its Speed under Sunny Day; couple this with Oddish's high Special Attack, and you'll find a powerful sweeper. Backed by Life Orb, Oddish can fire off very powerful STAB attacks that not many Pokemon can take.
SolarBeam should be the primary attacking move on this set, and with 120 Base Power behind it, opposing Pokemon will have a tough time switching in on Oddish. Sludge Bomb is also a great option thanks to its high Base Power and STAB. Hidden Power Fire is great on this set because all Fire-type moves are boosted by Sunny Day, not to mention that Hidden Power Fire rounds off nicely what would otherwise be poor coverage. Oddish has a shallow special movepool, so Sunny Day is the best option in the fourth slot, not only to support itself, but the rest of the team as well. Sleep Powder also works well because it lets Oddish incapacitate its counters and continue to sweep.
Team Options & Additional Comments >>>
Sleep Powder is a good alternate choice on this set because it can cripple Oddish's counters and allow Oddish to continue sweeping from there. However, if you choose to do this, it wastes a turn of sun, and Oddish loses precious coverage if you choose to use it over an attack move. Different Hidden Powers can also be used on this set; however, Hidden Power Fire is far and away the best choice. Oddish is also capable of running a double status set with Stun Spore and Sleep Powder; however, it is largely outclassed by other double powder users, such as Venonat and Paras.
Checks and Counters
With Sunny Day on the field, Oddish can be suprisingly hard to counter, obtaining excellent type coverage on most of the metagame. Munchlax is probably Oddish's best counter, being able to take all of its attacks and OHKO with either Fire Punch or Return. Snover is able to switch in on a supected SolarBeam, and either outspeed or just kill Oddish, now trapped because SolarBeam has to take a turn to charge, with Ice Shard. Revenge killing Oddish can be a bit easier thanks to priority attacks and fast Choice Scarf users. Croagunk is a good option to revenge kill Oddish, being able to KO it with Fake Out + Sucker Punch and stall Sunny Day turns in the meantime. However, Croagunk can be hurt a bit too, because Sunny Day damages Croagunk. 27+ Speed Choice Scarfers are good for revenge killing Oddish thanks to Oddish's low defenses and mere 26 Speed (in the sun). Examples of these would include Gastly, Gligar, Abra, or Ponyta.