Given a scientific passage and an answer, generate a question for the given answer.

Passage: Although lots of symbiotic relationships help both organisms, sometimes one of the organisms is harmed. When that happens, the organism that benefits, and is not harmed, is called a parasite . This type of relationship is known as parasitism. Answer: parasite
Although lots of symbiotic relationships help both organisms, sometimes one of the organisms is harmed. when that happens, the organism that benefits, and is not harmed, is called a what?