This is vintage 1980's or 90's Santa Cruz Speeds Wheels Scream clock. I'm not sure of the origin of this clock unfortunately. It could of been a store display/advertising from a skate shop or maybe some kind of kit clock or possibly homemade. The skater painted on the inside of the glass and the speed wheels scream logo are both painted in great detail.
If it is homemade someone definitely put some time and thought into it. The pool being skated on the inside appears to be a piece of styrofoam but it has a 3D look to it. It does have some wear to the frame throughout as you can see in the photos. It measures about 13 x 13 inches and 2.5 inches deep. The clock mechanism does work.
Feel free to ask any questions.