Quick answer

The “Mastadge” (sometimes spelled Mastidge) in the 1994 film Stargate wasn’t a real animal or a CGI creation—it was a practical costume built around real Clydesdale horses , with an animatronic head and clever rigging to make it look like a single alien beast.

What the Mastadge is (in-universe)

In the movie’s story, the Mastadge is:

  • A large, hairy, horse-like beast of burden used by the Abydonians.
  • Bigger than a normal horse, with a long neck , thick fur, and a distinctive hump.
  • Adapted to the harsh desert environment of Abydos (hot days, cold nights, sandstorms).

It’s essentially the “alien pack animal” you see Daniel Jackson feeding candy to and later being dragged by.

How it was actually made (behind the scenes)

The production used a mix of animal costumes, mechanics, and stunt work rather than digital effects. Here’s how they did it:

1. Real horses as the base

  • They used Clydesdale horses (large, strong draft horses) as the physical base.
  • These horses were costumed to become the fictional Mastadge.

2. The body costume

  • A skeletal frame was built from plastic tubing , covered with fabric and fake hair.
  • This frame stood 1–3 feet off the horse , especially around the head/neck area, to give the Mastadge its unusual shape and size.
  • The lower part of the costume was made of fabric and faux hair attached to leather straps , then fastened to the horse’s legs with Velcro.
  • The horse’s own lower-leg hair was dyed with non-toxic coloring to match the upper costume, so the transition looked seamless.

3. Weight distribution and stability

To keep the horse comfortable and the costume stable:

  • A pack saddle distributed the costume’s weight evenly.
  • Additional rump straps and a collar added stability.
  • The entire costume weighed around 150 pounds (≈68 kg).

4. Protecting the horse

Because they were filming in desert conditions:

  • The horse’s real head hung naturally underneath , shielded by loosely draped black netting in front of the face to keep sand out.
  • Animals worked in rotation so no single horse was overused.
  • They were allowed to wear the costumes for no more than three hours at a time , and were frequently washed down and rested in the shade.

5. The animatronic head

For scenes where the Mastadge needed to “react” (like taking candy or licking Daniel):

  • A mechanical/animatronic head was used.
  • This head was operated by a stunt person hidden under the costume , usually in the hump area.
  • In some close-ups where the full body wasn’t shown, the mechanical head was used as a separate prop , not attached to a horse at all.
  • When both the animated head and the full horse body were visible, a rider under the costume was radioed when to operate the moving parts to sync the motion.

6. Stunt work for action scenes

For the scene where Daniel gets dragged:

  • It wasn’t the actor being pulled; it was a stunt double.
  • The horse was cued to run from point A to point B , and the stuntman was dragged behind in a controlled way.

Why it looks so “alien”

The combination of:

  • An oversized, humped silhouette from the frame
  • Thick, matted-looking fur
  • A long, odd neck and unusual head shape from the animatronic

…sold the idea of a creature that was clearly horse-like but not quite a horse , fitting the “alien world” vibe without needing 1990s-era CGI (which was still limited and expensive).

Bottom line

  • The Mastadge = real Clydesdale horses + big fabric/fur costume + plastic-tube skeleton + animatronic head + hidden operator + stunt doubles.
  • It’s a classic example of practical effects : physical, on-set trickery rather than digital creation.

Information gathered from public forums or data available on the internet and portrayed here.