I have many cells but I don't have chloroplasts. I eat for energy, but I get to stay in one place.

The organism is fungi.

Explanation:

Organisms are classified into 5 kingdoms, Monera, Protista, Fungi, Plantae, and Animalia. The organism described in the question is fungi. Fungi is multicellular as they have many cells.

They do not have any structures that support locomotion, which is why they remain immobile. Unlike plants, fungi are not producers indicating that they do not synthesize food on their own. They obtain nutrients through absorption and in most cases, nutrients are obtained from decaying organic matter.

Fungi do not have chloroplasts.