From ScienceDaily:
One day in Myanmar during the Cretaceous period, a tick managed to ensnare itself in a spider web. Realizing its predicament, the tick struggled to get free. But the spider that built the web was having none of it. The spider popped over to the doomed tick and quickly wrapped it up in silk, immobilizing it for eternity.
We know the outline of this primordial worst-day-ever because the silk-wrapped tick subsequently was entombed in amber that may have dripped from a nearby tree. Its fate, literally, was sealed.
…
“It’s really just an interesting little story — a piece of frozen behavior and an interaction between two organisms,” he said. “Rather than being the oldest thing or the biggest thing, it’s nice to be able to preserve some animal interaction and show it was a living ecosystem.” Paper. (paywall) – Jason A. Dunlop, Paul A. Selden, Timo Pfeffer, Lidia Chitimia-Dobler. A Burmese amber tick wrapped in spider silk. Cretaceous Research, 2018; 90: 136 DOI: 10.1016/j.cretres.2018.04.013 More.
For non-ticks, this story is a trifle but it highlights the fact that new fossil finds are shedding some light on behavior as well as body size and shape among long-extinct life forms. For example, decades ago, teachers might assert confidently that dinosaurs did not look after their young (because that behavior had not yet evolved). Then came fossil evidence of nesting sites… It turns out, much complex behavior—including that of spiders—got started very early and not, apparently, through a long, slow process of evolution.
See also: Some dinosaur parents warmed eggs with their bodies
and
Dinosaur nesting site pushes back knowledge by 100 million years