Bladderwort (Utricularia spp.) is a relatively common carnivorous aquatic plant found in many lakes, ponds and wetlands. The small bladders along the stem that give the plant its name capture and digest zooplankton much like a pitcher plant catches an insect. Except it is a more active capture as a passing zooplankter triggers the trap door on the bladder and the vacuum within sucks in the microscopic animal.
Here is that process in slow motion, as a copepod triggers that reaction and becomes ingested, soon to be digested.