Design AtlasUX researcher Harry Brignull coined the term in 2010 with darkpatterns.org (now deceptive.design). Common types: pre-checked boxes (turning opt-out into fake opt-in), confirmshaming ("No thanks, I don't want to save money"), hidden costs, and the "roach motel" — easy to get into a subscription, deliberately hard to leave.
It's dangerous precisely because it borrows normal UI language (buttons, checkboxes) and points it against the user — the interface looks legitimate, so people don't even realise they were nudged. Since 2022 the EU has been tightening regulation against these patterns (DSA, Omnibus Directive).
The demo shows a pre-checked marketing opt-in, a tiny greyed-out "no thanks" link, and a big vivid "Continue" button. The warning badge calls out where it crosses the line.
When to use
When designing or reviewing a consent, subscription, or cancellation flow, ask: "if the user skims, do they end up doing the opposite of what they'd choose carefully?" If yes, it's a dark pattern.