Sentence:  &#91;[https://books.google.com/books?id=XsrvL26se48C&pg=PA22 page 22]&#93; Among the most illuminating and certainly the most bizarre of self-replicators are the digital organisms invented by Thomas Ray of the University of Delaware. [...] &#91;[https://books.google.com/books?id=XsrvL26se48C&pg=PA23 page 23]&#93; A peculiar creature that is 80 instructions long, but differs from the ancestral sequence by 20 or so alterations, has sometimes been observed; it is a <WSD>hyperparasite</WSD> able to force parasites to replace themselves with copies of itself. 
Meaning of the word marked with <WSD> tags:  Any parasite whose host is a parasite.