A clickbait advertisement for a web browser or mobile game, which usually involves a puzzle that must be solved (usually by pulling a pin) to prevent a character from getting hurt, lost, humiliated, etc (ex. being melted by lava). Notably, the actual gameplay is nothing like the advertised gameplay.
Has become a meme due to how pervasive they are, due to their use by games such as Hero Wars, Hero Rescue (even if reflective of actual gameplay), and most famously, the "-scapes" series of games by Playrix.