1) Fictional amorphous creature 2) Organism in a relationship 3) Symbiont 
Symbiont. 
Synonym for symbion ... Symbiont ... An organism associated with another in symbiosis. ... Synonym: mutualist, symbiote. ... Origin: G. Symbion, neut. Of symbios, living together ... (05 Mar 2000) ... 
(sim´bi-ōt) symbiont.
An organism living in symbiosis; usually the smaller member of a symbiotic pair of dissimilar size (also called the micro-symbiote); frequently, those micro-organisms associated in a regular mutualistic manner with insects and other invertebrates; usually preferred to 'symbiont'.
Type: Term Pronunciation: sim′bē-ōt Synonyms: symbion
symbiote An organism or species living in a state of symbiosis.