The Clock-trees- About 100,000,000 years ago this species started recording their history in chemical language. This intelligence developed despite a lack of what we'd consider full mobility, as the species is more like vegetation than animal-- they look like and behave like fruit bearing trees. Their general lifespan being as long as a tree's and the insights that being intelligent but immobile seems to have been a trigger for them to become transdimensional travelers. Amazingly they have the side ability of acting as a conduit for other non-capable individuals of any species.
The Clock-trees have been propagating themselves throughout the many universes, as well as thousands of habitable worlds within those universes, over that length of time.