I don't think this really needs a description... it's a tyrannosaur about to chomp an ornithomimid (obviously), in Late Cretaceous Mongolia. I do believe there is a similar drawing by Bakker in The Dinosaur Heresies, but my copy is in Australia. If anyone has a copy it would be great if you could send a scan/photo of the drawing to me (firstname.lastname@example.org). I want to see how it compares.
This painting is actually ANIMOOTED, but dA's pathetic video size won't show that to any great effect, so here's the still version.