The story
From clank + -er, onomatopoeic. The sense meaning "robot" appears in science fiction at least as early as 1958. Its broader popular use increased on social media beginning around 2024, due to the AI boom. In this wave of usage, it was especially influenced by the word's appearance in the Star Wars franchise, particularly the 2005 video game Star Wars: Republic Commando. In Star Wars, the term was used towards B1-series battle droids, which were humanoid robots that were manufactured for the sole purpose of fighting in armed conflicts. Their nickname of "clanker" stems from the fact that they would frequently make clanking noises any time they moved around due to being cheaply mass-produced.
Etymology from Wiktionary, CC BY-SA 4.0.