I, lichen.

This fungal individual makes lots of complex structures, on which microbes live. So do you.

A lichen is an ecosystem. It consists of a multicellular fungus that provides the gross structure of the lichen, and a community of microbes that live in and on that structure, including photosynthesizers.

A human is an ecosystem. It consists of a multicellular animal that that provides the gross structure of the human, and a community of microbes that live in and on that structure. A human, unlike a lichen, generally cannot photosynthesize. 

We usually see humans as individuals, but lichens as ecosystems. In the last few years some scientists have advocating deep thought about humans as ecosystems. There has been very little deep thought about lichens as individuals.