Chironex fleckeri
The Box Jellyfish is one of the most dangerous creatures known to exist on the planet. Like most jellyfish, the Box jellyfish does not have a specific digestive tract. The way that this jellyfish is able to obtain the nutrients that it requires to survive is that it uses cilia in its digestive cavity. What these cilia do is that they are able to move around gases, water, and dissolved food before absorption. By moving around the things inside the digestive cavity of the jellyfish, the food gets decimated to a pulp to make it easier for the animal to absorb its nutrients.