Type IV pili (T4P) are fascinating supermolecular machines that drive twitching motility, protein secretion, and DNA uptake in prokaryotes. T4P pili work as grappling hooks that cause bacterial twitching motility by a cycle of extension, surface attachment and retraction, making the cells move over a surface by pulling themselves along it. The properties of T4P as a motor have previously been scrutinized with biophysics techniques, but the mechanism of regulation of T4P activation dynamics in response to various environmental signals remained unclear, largely because numerous components coordinate to orchestrate the dynamics, and because T4P are very thin (~ 8 nm diameter) and therefore difficult to observe.