the.com/rabbit hole

means A tangent so absorbing that one click or question leads to another until you've burrowed deep into a topic and lost all track of time.

from Straight out of Lewis Carroll's Alice's Adventures in Wonderland (1865), where Alice tumbles down a literal rabbit hole into a disorienting, logic-bent Wonderland. The phrase stayed dormant as a vivid image for over a century before the internet era repurposed it — 'going down the rabbit hole' became shorthand for the way one webpage, Wikipedia link, or forum thread pulls you into an ever-deeper, disorienting maze you didn't mean to enter.