You are disoriented. Blackness swims toward you like a shoal of eels who have just seen something that eels like a lot …

Douglas Adams (1952–2001) English author, humorist, screenwriter

Game (1984), The Hitchhiker’s Guide to the Galaxy, Infocom [with Steve Meretzky]
    (Source)

Text that comes up (sometimes) when the protagonist loses consciousness or is in pitch darkness. When this condition is corrected, the counter-message comes up:

You are disoriented for a moment. The blackness swims away like a shoal of eels who have just seen something that eels like a lot half a mile away ...

The text is often misquoted as a "school of eels" (and the date mislabeled as 1985).