Internet tunnel [or ‘internet k-hole’]:
(n) Impulsive-yet-not-random, thematic internet navigational trajectory that leads a user through various websites or pieces of content that include a variety of media (i.e. text, pictures, animated GIFs and video) in such a manner that when one ‘emerges’ from said tunnel, one is viewing something entirely unrelated to the ‘doorway’ (first piece of content in tunnel). Popular tunnel themes include porn, conspiracy, creepy, Wikipedia, and apocalypse scenario.
Example: “Lost four hours this morning to an internet tunnel. Can’t even remember why I got online…””—McSweeney’s Internet Tendency: List: Proposed Additions to the Internet Lexicon.