Modifiers matching protozoan:

• parasitic,
• larger,
• sessile,

Simple categories matching sessile:

• polyp,
• shellfish,
• resource,
• invertebrate,
• organism,
• mollusc,
• animal,
• predator,
• fauna,
• prey,
• cnidarian,
• taxon,
• creature,
• form,
• ciliate,
• echinoderm,
• benthos,
• bivalve,
• coelenterate,
• protozoan,