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The Mental Institution is the final boss of Serious Sam 2 and the penultimate boss of Serious Sam: Tormental.


The Mental Institution is Mental's home in Serious Sam 2 and a pyramidal mobile fortress, and also has a spaceship for an escape emergency (such as Sam's arrival there). When Sam defeats all the enemies around the Institution, it will activate its wheels and start moving towards him.

Sam encounters a representation of the Mental Institution within Mental's mind in Serious Sam: Tormental, fought as the fifth proper boss in the game and the boss of the Fortress area. Defeating it opens a portal to the Vault, making it the final boss of the game until the Vault door is opened.


Serious Sam 2[]

The Mental Institution has a vast arsenal of weapons: fireball launchers, cannons, rocket launchers, and the ability to spawn a mass force of Fatso Fighters and Seagull Fighters. Going near the Institution's wheels will result in instant death.

  • Its first attack are three waves of modified fatso fighters that will crash into the player.
  • Its second attack is to launch fireballs at the target.
  • The third attack consists of three waves of modified seagull fighters. Unlike the regular counterparts, each one has a larger amount of bombs than the regular fighter, making it nearly impossible to dodge completely.
  • The fourth attack consists of shooting cannonballs at the player.
  • The fifth attack consists of three waves of regular fatso fighters
  • The sixth attack consists of firing a large amounts of missiles.
  • After that attack, the core stays exposed until the end of the fight. If the player does not finish the boss quickly, it will splatter them with its wheels, killing them instantly.

Serious Sam: Tormental[]

Like its appearance in Serious Sam 2, the Mental Institution is the largest enemy in the game and boasts a wide variety of projectile attacks to hurl at the player, gaining additional attacks as it takes damage. This time it is wholly stationary however and the only enemy in the game to not cause any contact damage. It attacks solely via its two large cannons, each of which attacks independently of the other.

At any time, each cannon can fire...

  • a random spread of bullets.
  • three lines of bullets in a cone formation.
  • bombs into the arena that explode shortly after the player makes contact with them.
  • two clusters of bullets that then spread outwards in all directions.
  • large green energy spheres that chase after the player and explode on contact.
  • spinning projectiles that bounce off walls.
  • a spread of green projectiles that slowly home in on the player.
  • large red projectiles that start slowly but then gain in speed, exploding upon reaching the player, a wall or the ground.


Serious Sam 2[]

  • The fight itself is pretty straightforward, just rush backwards and shoot any projectile or enemy it spawns, grab the repair power-ups to survive and attack it when its core is exposed, especially if the player has Serious Damage. Albeit having 1,000,000 HP, it takes very heavy damage when shot at the core. If the player's vehicle is destroyed, they will die, although they will not immediately die if ejected from the vehicle.
  • The most important thing to take care of first, as said above, is the fatso fighters spawned by it, as they will deal tons of damage if they get the player with their lasers and then crash on them, so the player should take them out as soon as possible. seagull fighters are also a threat, but shooting the core is a higher priority rather than shooting them. Of course, if the player can dodge the fatso fighters while the core is open, they can just shoot it and evade them.
  • Usually, the boss should be done for during the cannonball phase without serious damage or fireball phase if the serious damage was grabbed earlier.

Serious Sam: Tormental[]

  • Just like in Serious Sam 2, the fight revolves around attacking the crystalline core in the center of the Mental Institution, which is periodically shielded. Unlike Serious Sam 2 however the shield does not open up on its own. Instead the player needs to destroy the shield generator pillars that spawn in the arena, which forces the core to reveal itself for a short time. More shield generators spawn as the Mental Institution loses health.
  • Since the Mental Institution only attacks with projectiles, apart from the occasional bombs, items like the "Buddy Decoy" and "Buddy Crabby" are incredibly useful. The former pulls the attention of the cannons away from the player, while the latter blocks incoming projectiles.

Behind the scenes[]

  • In the original trailer for Serious Sam 2, two Ugh-Zans can be spotted walking towards the player. Why they were cut from the game is unknown, but their roars can still be heard throughout the level.


  • Apparently, there are other residents living in the Mental Institution aside from Mental. The other residents are, as seen in the cutscene when the player finishes the Mental Institution level: "Napier", "Luthor", "Moreau", "O.J.", "Vader", and of course Mental himself.
  • With 1 million HP, the Mental Institution has the highest health points of any enemy/boss in the series.
    • When it comes to size, though, it is beaten out by Ugh-Zan VI from Serious Sam 4, who stands 475 m (1,558 ft) tall.
  • The battle with the Mental Institution happens only in the PC version of the game. It was added in the game during the last months of the development cycle.
  • Upon beating the boss, a cutscene is cued. Sam presses Mental's name on the residence list, but when the camera angle changes, he seems to be pressing a different button.


List of appearances[]