http://www.sciencemag.org/news/2021/06/these-cauliflowerlike-anemones-snack-ants

Scientists long suspected the giant plumose anemone (Metridium farcimen), which flourishes along the U.S. Pacific coast, lived off a respectable ocean diet of zooplankton and tiny marine invertebrates. A new study shows they were mostly right. But when given the chance, the cauliflower-shaped sea creature also feasts on an unusual culinary delight: ants.

To find out what the anemones were eating, researchers collected 12 anemones near docks off the coast of Washington state and analyzed their stomach contents. Using a process called DNA metabarcoding, which looks at DNA from a sample and matches it to a list of species in an online database, they found that the anemones ate crab larvae, barnacles, and plankton. But about 10% of their diet was made up of ants, they report this month in Environmental DNA.