Modifiers matching protozoan:

• larger,
• sessile,
• parasitic,

Simple categories matching sessile:

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