Is slime mold unicellular or multicellular?

Slime mold is one of the most interesting protozoa. Every single cell in a slime mold is, in and of itself, a fully functioning microorganism, and each cell could thrive on its own. Yet, when many of these cells come together, they start acting like a single organism. They work together to move and find food. So the truth, is that a slime mold is multi-cellular, but it is not a single living breathing organism like a fungus.