A scientist discovers a new organism the organism is multicellular eat other organisms for food and moves freely from place to place the organism most likely belong to

Kingdom Animalia (Multicellular Heterotrophs)

Explanation:

Heterotrophs (animals) cannot make their own food like the green plant (autotrophic mode of nutrition). So they have to search for foods by moving about. They can feed in plants, other organisms /animals or feed on dead materials.

Animals are multicellular (with many specialised cells). For example the cell in our nose are meant to respond to smell while that of the eyes are specialised for light capture. Our muscle cells focused on movement. Unlike the plants, animals lack cell walls.