Grass, hypocritical lefty that he is, seems to be invoking the eel as something evil, sinister, and dirty. In fact, I know of nothing whatsoever sinister about the good old Sargasso-bred American and European eel (the moray is another matter, and the "electric eel" isn't even an eel at all). In fact, Wikipedia insists that fishermen at the coasts catch eels and keep them as pets. I have read nothing about them being attracted to horse's heads (what, they're eaters of carrion?), much less "pollulating" in them.
This whole thing is way beyond me. Grass seems to be stereotyping eels because they are fish that look like snakes. Otherwise they seem perfectly harmless (though not kosher).
This is the sort of stereotyping you'd expect from a liberal hypocrite.
Read up on the “hagfish” ... which may or may not be a fish ... is certainly not an eel even though sometimes called one ... and is thoroughly disgusting.