Hannibal Lecter's aquarium

Take a fairly thin layer of plasma. Remove the clotting factors. Warm it to a temperature somewhat below that of a healthy human body. Aerate it with an aquarium pump connected to an oxygen cylinder. Meanwhile, culture human, tissue in a Petri dish, including cardiac muscle cells, including a Bundle of His and the rest of the cardiac conduction system, but very thin, until you have a disc of cardiac muscle, and i'm talking really wafer-thin here.
Carefully transfer this pulsating disc into the plasma. It will survive on the solutes in the plasma, including oxygen, though obviously that will need replenishing, and will swim through the water like a jellyfish.
In the meantime, grow fronds of HeLa cells for the bottom of the aquarium to resemble seaweed or bryozoa, and culture other cells which can survive in relatively harsh conditions for the human body, such as hyaline cartilage, fibroblasts and corneal epithelium, moulding various simple "organisms" from them. Sponges which use ciliated respiratory epithelium, worms and salp-like plankton based on corneal epithelium and so on. All one cell layer thick to allow nutrition and diffusion of respiratory gases, fed by "fish food" flakes consisting of amino acids, minerals, vitamins and lipids, all in a sterile environment, connected to oxygen tanks and a dialysis machine. An aquarium made up entirely of human tissue. Good defence when they find what's left of the bodies too. "It's not murder - they're still alive."