They may be referring to Norton's Dome, a thought experiment involving a stationary ball ontop of a cone in which the ball can spontaneously begin moving at any

They may be referring to Norton's Dome, a thought experiment involving a stationary ball ontop of a cone in which the ball can spontaneously begin moving at any time and still allegedly be obeying Newtonian dynamics: https://en.m.wikipedia.org/wiki/Norton%27s_dome https://en.m.wikipedia.org/wiki/Norton%27s_dome