"Ocean Invasion #1: Octopus arborealus" by Daniel D. Brown.
(Posters available.)
Non-aquatic cephalopods are notoriously under-represented, if not completely absent, in the fossil record since they are mostly composed of soft-tissue and, unlike their aquatic counterparts, live in environments without a constant rain of fine sediment and ubiquitous muddy ground necessary for soft-tissue fossilization.
Given this explanation for a lack of fossil evidence, it cannot be ruled out that the scenario depicted above -- predation by giant octopuses newly colonizing an above-water world unprepared for their arrival -- is what really doomed the dinosaurs to extinction. Only those dinosaurs that were able to rise above the now-deadly trees -- birds -- survived the transition to a post-tree-octopus environment.