Hello Neighbor is a stealth horror game released in 2017, built around sneaking into a suspicious neighbor's house while he tries to catch the player. Its title became a recognisable greeting online because the neighbor himself is the central threat, so saying hello to him sounds both polite and risky. Short voice clips playing on that contrast spread through gaming edits, meme compilations and soundboards, where the line works as a quick reference fans instantly recognise. It remains popular because the joke needs no setup beyond the greeting itself.