- Oh, you're a big one, ain't ya?
- — Sam
Ugh-Zan III is one of Mental's generals, ranking as Great Admiral in Mental's Horde. Ugh-Zan III is the third incarnation of the vicious Ugh-Zan, the last of the warlock giants. He was sent by Mental to supervise the assault on Earth. He is one of the most dangerous creatures in the universe.
Ugh-Zan III is a very large creature but very slow. He moves at the same speed as the player does (10 speed in the database, just like Sam), has 4 arms, which come with 4 weapons, can breathe fireballs or stomp the player and can regenerate his health when it's low. He regenerates his life when he has about 5% health left (when the life bar turns red and is nearly empty). He is stunned, disabled and immobilized when hit by the laser beam, so in that case he can't regenerate.
The boss fight comes in 3 stages: running away from him, waiting for the Pyramid Door to open, and the last fight. In the first stage, you just run away from him, as he chases you through the Arena to the Great Pyramid. While you're doing this, Biomechanoid Minors, Biomechanoid Majors, Kleer Skeletons, and Sirian Werebulls are rushing you.
In the second stage, you will have to survive against him until the Pyramid Door opens, which will take some time. Ugh-Zan will take out his Lava Bomb Launcher and Laser Gun when he reaches the Pyramid's ramp.
In the third stage, he will jump inside the Pyramid Arena, pull out all his 4 weapons (Lava Bomb Launcher, Rocket Launcher, Laser Gun and Electric Gun). To kill him, you will have to activate all four rings around the arena, get him in the middle and zap him with the spaceship's laser beam. In SSHD, a laser beam is automatically fired once when you enter the pyramid.
- The player should not get close to Ugh-Zan (obviously). His stomp is only survivable in Easy and Tourist difficulties, as the player can have up to 300 health and armor and Ugh-Zan's stomp will only deal 500 damage there.
- His rockets and lava bombs/balls are destructible, so try to shoot them if you can't dodge them.
- Try to avoid the laser beams by sidestepping, and the lava bombs by changing direction, since they use the same targeting system as Lava Golems. The Electricity Gun will spread more widely in SSHD than it does in Serious Sam 1.
- The SBC Cannon is definitely the most viable weapon to use against him, followed by the XL2 Lasergun, MK III Grenade Launcher and XPML21 Rocket Launcher. The XM214-A Minigun can be decent, but just make sure you have enough bullets.
- Take note that the first time the laser beam fires upon Ughzy (from the mothership) will have a slight delay, as the Mothership's gates have to open.
In Serious Sam HD: The Second Encounter, Ugh-Zan III is a playable multiplayer character if one either pre-ordered SSHD: TSE or obtained the Serious Eight DLC. This version of Ugh-Zan III has been scaled down to be as large as Serious Sam nor has he any of his larger counterpart's abilities. Being Ugh-Zan III is just a cosmetic change.
- Early versions (from 1998–1999) of Ugh-Zan had him holding a minigun and a shield.
- Ugh-Zan was supposed to have 3 heads: his current head, a goat head and a skull head. These heads can be found as Ugh-Zan's icon in Test 1 Editor.
- In the PC version Serious Sam 1, Ugh-Zan had no fingers, while in the Xbox version of Serious Sam 1 he did.
- Two Ugh-Zans can be seen in Serious Sam 2's original trailer on The Final level, however, in the PC version they became replaced by battle with Mental Institution. Yet you can still hear their idle roars in the background if you have the music settings lowered.