The Ustanak is a tall and muscular creature with extremely pale skin and a few remnants of long, wispy white-blonde hair. Its body is covered with deep gashes and there is evidence of surgical enhancements. Its face is horribly distorted and twisted, skin overlapping and stapled down in sections. Only one eye is visible, set deep in its skull with the eyebrow ridge hanging over it and its mouth is left agape with only the lower part of the jaw seeming human.
Its most notable feature is its right arm, which was possibly surgically attached as seen by evidence of the skin being stapled together around the right pectoral muscle. The arm seems to be designed to use a multitude of accessories, such as a large hydraulic-powered claw with needles to grab targets and collect blood samples to several mining drills to break through rock walls or a Chain Gun attachment. The Ustanak will alter its equipment depending on the environment it deployed in. Other evidence of cybernetic enhancements exists, such as the mechanical fingers seen on its left hand and a row of metallic plates along its spine. On one occassion, the Ustanak has a human-sized cage attached to the back of a strap around its torso that it will use to keep a target out of commission. There is an organ on the creature's back that dispenses Oko B.O.Ws which it uses to detect its targets.
The Ustanak pursues its target ruthlessly but remains completely loyal and obedient to Carla Radames, carrying out her orders without hesitation. It is quick to alter its combat abilities depending on the situation, such as attaching a chaingun to its arm when assaulting a helicopter and will swap its arm attachments frequently. This is evident during the fight against Jake, Sherry, Leon, and Helena where it swaps out the claw it uses to capture Jake for a shotgun in order to eliminate the other characters. Despite its size, the creature is extremely fast, able to keep pace with its targets and catch up to them easily. Although its primary offensive tool is the weapons on its right arm, the Ustanak is more than capable of holding its own without this device and will engage foes in hand-to-hand combat if necessary.
Like the majority of the B.O.W.S created by the C-Virus, the Ustanak is extremely durable and can survive presumably fatal attacks including immolation, loss of limbs and getting impaled with a mining drill. However its intelligence surpasses other B.O.W.S such as J'avo.