Brian Switek of Smithsonian's Dinosaur Tracking blog has a lovely story about a little-known exhibit at the Dinosaur Museum in Blanding, Utah. The mechanical Brotosaurus (reminder: it's not a real dinosaur!) displayed in a small glass case was the original stop-motion model used in the 1933 King Kong movie and its sequel, Son of Kong. The special effects model has deteriorated over time, revealing the intricate metal joints and armature that gave it lifelike movement in the seminal monster film. Director Peter Jackson has often gushed over how influential the film was to his career, which prompted his 2005 remake. The original Kong armature was Jackson's guest at the premiere of his movie and sat on his lap during the screening. It was sold at auction for $200,000 in 2009. Another Brontosaurus model from the movie was sold for $40,000 in 2010.
This is the original model that was used as the Brontosaurus in King Kong and the more fanciful sea beast in Son of Kong. It is very unique because it was designed like a stop-motion model, but modified with cables so that it could be used for live-action photography. This was necessary for scenes in which the model had to rise out of the water and splash about while attacking the actors. The "actors" in these scenes were also miniature puppets that were loosely jointed so they would move naturally as the dinosaur tossed them about.
The San Diego Natural History Museum's dinosaur exhibit has a larger photo of the model, in addition to a studio archive photo showing an effects technician posing the miniature for the painstaking shoot back in 1933 for Son of Kong.