Exeggutor

Exeggutor is arguably the most reliable sleeper in RBY Ubers. Its relatively accurate Sleep Powder and good stats mean it will almost always manage to put a foe to sleep. This, alongside Stun Spore, allows Exeggutor to provide incredible team support that facilitates strong sweepers like Slowbro and Mewtwo. Exeggutor also has access to Explosion, meaning it will always pose a threat even after it has finished spreading its status, effectively making it a two-for-one in an ideal scenario. Exeggutor's stats are very well-rounded, boasting excellent bulk that allows it to check threats such as Snorlax, Tauros, and Mew under the right conditions. It can even check Mewtwo not carrying an Ice-type move. Moreover, Exeggutor's niche is unique, as no other Pokemon has the combination of a sleep move, a paralysis move, and Explosion. Exeggutor also hits very hard and can effectively pressure foes such as paralyzed Pokemon, Snorlax, and Chansey with Special drops from Psychic.

However, Exeggutor does have a few flaws. It is forced out by strong Ice-type attackers such as Jynx, Cloyster, Articuno, and Lapras, as well as Mewtwo if it is carrying Ice Beam or Blizzard. Exeggutor's lack of coverage means it is reliant on Psychic and Explosion to deal damage, causing it to struggle to damage other Psychic-types and Chansey without using Explosion. Exeggutor is also very slow for Ubers, and it will usually take a hit before it can do anything, often forcing it to use Explosion earlier than it would like to. Also, Exeggutor lacks any kind of recovery, and players must be aware of the risks of switching Exeggutor in against attacks like Tauros's Body Slam.