The U-8 is a gigantic Bio-Organic Weapon that appears as a boss in Resident Evil 5. Though one of the largest B.O.W.'s on record, its size hasn't been accurately measured, though it is large enough to stand above any known land-based armoured vehicle. The base genes for producing the U-8 are also unknown, but given the crab-like shape of the creature it is safe to assume that TRICELL incorporated crab DNA in its design. What is confirmed is that TRICELL also utilized the genetic code of the Type-2 Las Plagas when producing this monster.

TRICELL created at least one U-8 prior to the Kijuju Incident in 2009. BSAA agents Chris Redfield and Sheva Alomar encountered this creature in TRICELL's secret Uroboros Laboratory within an extensive revolving elevator shaft. The U-8's legspan took up the entire width of the shaft and it would use its forelegs to attack Chris and Sheva, attempting to crush them with its giant claws. The creature would also release swarms of "drones": insectoid creatures resembling large mosquitoes that would fly directly at targets and impale themselves upon them. These mosquito drones were not biologically related to the U-8 and were created separately.

The body of the U-8 was protected by a thick layer of chitinous armour. However, the armour was weaker around the joints on its legs and immediately over its head. Firing on the exposed joint tissue allowed Chris and Sheva to stun the creature, then they were able to penetrate the carapace on its head with concentrated shotgun fire and explosives. Firing directly into the creature's open mouth appeared to do the most damage.