Beheeyem looks like a fearsome pokemon with that monstrous sp attack and that pretty great move pool with analyze on top. But it faces a huge problem: its slow REAL slow. And it has pretty mediocre defense to effectively tank and in OU its just pursuit fodder in UU it can be good but it good buts faces stiff competition from other psychics. It does make a nice trick room sweeper though.
Sp. Attack: 125
Sp. Defense: 95
Attempt At Being a Special Tank
Nature: Modest / Quite
Evs: 244 HP / 252 Sp. Attack / 14 Sp. Defense
Ivs: 0 Speed
-thunder wave / substitute
-shadow ball / thunderbolt
Beheeyem has recover and a bunch of support moves which can be good. Psychic is you manatory stab move here with it you will do massive damage on many things. Recover obviously heals up which helps you tank better and aids substitute if you use it. Thunder wave and cripple switch-ins or substitute if you want to attack from behind a substitute which also allows you to escape and pursuiters if they come in on the switch. Shadow ball does massive damage to other psychic walls coming in or thunderbolt for good coverage. The evs maximize your offense and defenses to tank sweep as best as you can. Since you donít worry about speed here modest is the best option but if on a trick room team quite is good. Same with the ivs if used on a trick room team you need as little speed as possible. 244 HP gives you a leftovers number if you want maximum HP go ahead but your only going to get 2 HP.
Trick Room Sweeper
Item: Life Orb / Choice Specs
Ability: Analyze / Synchronize
Evs: 252 HP / 252 Sp. Attack / Sp. Defense
Ivs: 0 Speed
-energy ball / substitute / trick room
Beheeyem is a monstrous sweeper under a trick room boasting that 125 special attack. Psychic is a great stab move shadow ball for pyshic type special walls and thunderbolt for bulky waters. Energy ball is mostly filler but does allow you to hit lanturn hard. If you are on the life orb path then consider substitute as with the first set allows you to hit behind a sub or not die from pursuiters. Trick room is a possible option here as filler but generally you donít have the bulk to set it up. Life orb if you want more choice or choice specs if you want the power. Arguably though life orb is better with that trick room clock ticking. The evs maximize your HP to take possible hits and special attack to sweep. Quite and 0 speed ivs are needed to sweep under trick room. Analyze is the traditional choice but it does not effectively work in a trick room due to you being faster. So if you wish synchronize is an option.
Calm Mind Tank
Evs: 244 HP / 252 Defense / 16 Sp. Attack
-shadow ball / thunderbolt / recover
Again with that strong offense it doesnít need much more of a boost but it is ok to add a bit more and with even more defense with it. Basically just substitute up on a switch or calm mind up on a special wall trying to tank. Substitute gives you a free turn to clam mind straight up attack or switch on a pursuiter if used with the right prediction its deadly. Psychic is great stab and shadow ball and thunderbolt are great for coverage. Recover is ok to heal but you do lose out on coverage. The evs here maximize up your defense to take defense hits if needed. Not the best with this set up itís a great surprise.
-Wall breaking is an interesting one if you toss in a bunch of speed. But you lose out on many walls barely with that speed and choice scarf is stupidly overkill here.
-Psycho shock is worth a mention to break through walls. But generally you donít have the move slot for it and the power drop is big. Although it can be used if your using a ďfiller moveĒ as with the trick room sweeper.
-Toxic is an option over thunder wave but then again lower speed really helps you out.
-You donít have enough bulk for charge beam nor the time. Same reason why nasty plot isnít a great option.
-Guard swap can be a surprise but its rather gimmicky.
-Wonder room might help out a few of your walls. Must be prepared to make a team around it though.
-Numerous hidden powers are possible. Hidden power fighting or ground are notable ones.
-seek out pursuiters if you have a problem with lets say absol get a registeel
-special walls can be a problem so physical attacks
-a trick room team
-special and physical walls
-slower pokemon (trick room)
UU works well there any higher and it sucks
a little lower... its just not built for calm mind...