Zuul has been estimated to have been 6 metres (20 ft) long, with a weight of 2.5 tonnes (5,500 lb).

The describing authors of Zuul, Victoria Arbour and David Evans, noted some distinguishing traits of Zuul.
Some of these were autapomorphies, unique characters which set Zuul apart from all other known ankylosaurids.
The caputegulae, armour tiles of the head, that lay on the nasal bones, the frontals and the parietals, are imbricated, overlapping, and pointed on top.
The squamosal horns, on the rear corners of the skull roof, have conspicuous longitudinal grooves on their side surfaces.
The osteoderms on the side of the tail, the knob itself excepted, have a front edge with a strongly hollow profile, while their points are off-set to the rear.
The tail knob is vertically flattened with a height less than a fifth of the length.

Other traits were not unique but distinguished Zuul from various relatives in the Ankylosaurinae.
The caputegulae on the prefrontals, the frontoparietals and the middle supraorbitals are pyramid-shaped, in contrast to the conical caputegulae with Nodocephalosaurus and Talarurus.
The squamosal horn protrudes to behind the rear edge of the skull roof, just as with Scolosaurus but different from Anodontosaurus, Euoplocephalus or Ziapelta.
The caputegulae behind the eye socket are small and sparsely distributed, again like Scolosaurus but differing from Anodontosaurus, Euoplocephalus or Ziapelta.
The osteoderms on the handle of the tail club are relatively larger and more pointed than those of Asian ankylosaurines of the Nemegt Formation of Mongolia.
Zuul has been estimated to have been 6 metres (20 ft) long, with a weight of 2.5 tonnes (5,500 lb).
The describing authors of Zuul, Victoria Arbour and David Evans, noted some distinguishing traits of Zuul. Some of these were autapomorphies, unique characters which set Zuul apart from all other known ankylosaurids. The caputegulae, armour tiles of the head, that lay on the nasal bones, the frontals and the parietals, are imbricated, overlapping, and pointed on top. The squamosal horns, on the rear corners of the skull roof, have conspicuous longitudinal grooves on their side surfaces. The osteoderms on the side of the tail, the knob itself excepted, have a front edge with a strongly hollow profile, while their points are off-set to the rear. The tail knob is vertically flattened with a height less than a fifth of the length.
Other traits were not unique but distinguished Zuul from various relatives in the Ankylosaurinae. The caputegulae on the prefrontals, the frontoparietals and the middle supraorbitals are pyramid-shaped, in contrast to the conical caputegulae with Nodocephalosaurus and Talarurus. The squamosal horn protrudes to behind the rear edge of the skull roof, just as with Scolosaurus but different from Anodontosaurus, Euoplocephalus or Ziapelta. The caputegulae behind the eye socket are small and sparsely distributed, again like Scolosaurus but differing from Anodontosaurus, Euoplocephalus or Ziapelta. The osteoderms on the handle of the tail club are relatively larger and more pointed than those of Asian ankylosaurines of the Nemegt Formation of Mongolia.
Zuul