Exeggutor is a bit of a mixed bag. Defensively, it has resistances to Ground-, Electric-, Water-, and Fighting-type attacks that allow it to check a wide variety of threats, including Marowak, Vaporeon, and Machamp. However, its low Special Defense and weaknesses to Ice-, Fire-, Dark-, and Bug-type attacks leave Exeggutor vulnerable to being Pursuit-trapped or being hit hard by a surprise Hidden Power Bug, Ice Beam, or Fire Blast from one of the threats it is supposed to check. On the offense side of things, it gets access to Sleep Powder, Explosion, Stun Spore, and Leech Seed in addition to a high Special Attack stat off of which to run a strong STAB Psychic. However, it usually needs to choose between using either Giga Drain or Hidden Power Fire for coverage, which tends to leave it stuck against either Skarmory or Tyranitar, both of which resist Exeggutor's other attacks, including Explosion. While it has its limitations, Exeggutor can be a nightmare to deal with if one is not well-prepared for it, and it usually ends up taking at least one opposing Pokemon out of the game.
Psychic is Exeggutor's main attacking move that allows it to punish opponents that try to over-predict against Exeggutor, since the dual-threat of Explosion and Sleep Powder can force a lot of switches. Running off 348 Special Attack, Exeggutor can do heavy damage to Pokemon that are not named Snorlax or resistant to it. Unfortunately, Psychic is resisted by quite a lot of Pokemon, including Skarmory and Tyranitar, the latter being immune to it. Furthermore, these foes also resist Exeggutor's Explosion, and to top it off Exeggutor cannot cover both of these threats with just one coverage move. Giga Drain is typically chosen to deal with Tyranitar since it is immune to Psychic and can Pursuit Exeggutor to death, although Hidden Power Fire can be used to deal heavy damage to Skarmory and Forretress instead. Giga Drain is chosen over Hidden Power Grass for dealing with Tyranitar because, although Hidden Power Grass is stronger, both moves 3HKO Tyranitar while Giga Drain heals Exeggutor to avoid the guaranteed 2HKO at the hands of Crunch or Fire Blast. However, thanks to Sleep Powder, even though Exeggutor can't have enough attacks to damage everything it wants to, it can still threaten to incapacitate what it can't outright attack. Exeggutor can also use Stun Spore to spread status more readily without having to worry about Sleep Clause. This works best if your team already has another Pokemon with a sleep-inducing move. Finally, with Explosion, Exeggutor can take out a special wall such as Snorlax, or a RestTalk user—such as Zapdos or Raikou—that can avoid being 3HKOed by Psychic and absorb sleep to boot.Team Options & Additional Comments >>>
Exeggutor has plenty of other tricks up its sleeve. You could use both Sleep Powder and Stun Spore for a double powder set, although this leaves Exeggutor without a coverage move for either Tyranitar or Skarmory. In addition, Leech Seed is an interesting option for forcing even more switches, as the residual damage and healing can turn otherwise poor match-ups for Exeggutor into winning ones. Leech Seed is often used with Stun Spore and Substitute on a SubSeed set, and it is effective at forcing switches and spreading status throughout the team. SubSeed is especially effective if Spikes are down to punish the inevitable switching the opponent is bound to do. Exeggutor could also ditch the status move on the standard set and instead run an all-out attacking set with Psychic, Giga Drain, Hidden Power Fire, and Explosion. The power of this set is that it ensures that Exeggutor will be able to damage Normal-resistors enough to pull off a relevant Explosion. The downside, of course, is that Exeggutor tends to thrive off its ability to threaten status and punish the switches that result from this threat. Synthesis and Moonlight are options to give Exeggutor a reliable recovery option, but Exeggutor is less a tank and more an instant offensive threat, so giving up an offensive move for healing is not recommended. Exeggutor also gets access to Reflect, which can assist a Leech Seed set in tanking Snorlax, but in general Exeggutor wants to be attacking and inflicting status, not setting up screens.
Checks and Counters
Sleep Talk Zapdos and Raikou are the most common counters to Exeggutor, as they absorb sleep and can threaten Exeggutor out with Hidden Power Ice. In addition, other Sleep Talk users such as Snorlax, Suicune, and Vaporeon can all absorb sleep and take Exeggutor's attacks well, although the Sleep Talk using Water-types should be wary of Giga Drain's potential 3HKO, even if Exeggutor can be easily stalled out of Giga Drain's meager 8 PP. Sleep Talk Vaporeon is a particularly shaky switch-in because it needs to set up multiple Growths before it can force Exeggutor out, although if you predict a Sleep Powder, Vaporeon can take it with the best of them. Note that Exeggutor also has the power to Explode on all of these threats, so even though they can absorb sleep and take its hits, Exeggutor is looking precisely for these match-ups so it can Explode to take these Pokemon down.
Skarmory and Forretress are incapacitated by sleep, but otherwise resist Explosion, threaten Exeggutor with their STABs, and resist both Psychic and Giga Drain. However, Hidden Power Fire variants can spell trouble for them, especially in the case of Forretress. Tyranitar, on the other hand, is also vulnerable to sleep, but is immune to Psychic, resists Explosion, and can threaten Exeggutor with Fire Blast and Crunch while nailing it with Pursuit if it switches out. However, Exeggutor can threaten with Giga Drain, which not only 3HKOes Tyranitar but also heals Exeggutor enough to prevent even Fire Blast and Crunch from guaranteeing a 2HKO, so Tyranitar generally cannot just switch into Exeggutor and spam Pursuit to defeat it. Some more complete counters include Umbreon and Houndoom. These Pokemon can take Psychic, Giga Drain, and Hidden Power Fire. Umbreon can outspeed and use Charm to render Exeggutor's Explosion useless, use Toxic to cripple it, and use Pursuit to do 43-50% to it if it switches out. Houndoom, on the other hand, simply outspeeds and is likely to OHKO with Fire Blast or do 62-73% with Pursuit if Exeggutor switches out. However, these counters are vulnerable to being hit by Sleep Powder or Explosion on the switch.
Other checks to Exeggutor include Starmie and other Exeggutor. Starmie can check Hidden Power Fire variants or even attempt to use Recover to stall out Giga Drain's 8 PP, and is usually the best sleep bait available on a defensive team without Sleep Talk. However, losing Starmie to sleep, Explosion, or a critical hit Giga Drain will leave Cloyster open to set Spikes up. Furthermore, your own Exeggutor can switch into an opposing Exeggutor to threaten it in return with Explosion, Sleep Powder, or potentially even Hidden Power Fire. However, keep in mind that your own Exeggutor works best against Giga Drain Exeggutor, and that furthermore the opposing Exeggutor will also have all of these tools to use against you. There are also Pokemon that threaten Exeggutor but cannot wall it or switch in on it easily. Charizard does not want to take status or 35-42% damage from Psychic on the switch, but is likely to OHKO with Fire Blast or set up Belly Drum if Exeggutor chooses to switch out. Additionally, Heracross cannot switch into 65-77% damage from Psychic, but it often runs Sleep Talk to absorb sleep and forces Exeggutor to switch out with the threat of a guaranteed Megahorn OHKO.