A named American business phenomenon with its own literature, its own software features and its own prevention advice: the gradual expansion of a project beyond what was agreed, without any corresponding change to fee or timeline.
It begins small. One more interview, a slide deck summarising the findings, a follow-up workshop. A consultant contracted for three research workshops and a report can end up delivering forty percent more work for the original fee.
The word exists because the behaviour is normal enough to need a name. Creep is the giveaway — nobody decided it, and it happened anyway.