Once on a morning walk in Melbourne, a devotee who was following close behind, eager to hear everything that Srila Prabhupada said, made the blunder of accidentally stepping on his guru’s heel. Srila Prabhupada stopped, turned around, looked admonishingly at disciple, then turned back and continued walking. Shortly thereafter, that disciple made the same mistake. Srila Prabhupada again turned and looked at him, longer than previously. When the disciple did it for a third time, Srila Prabhupada turned and whacked him hard with his cane. Without saying anything, Srila
Prabhupada turned back and continued walking.

Told by Sukla-devi Dasi, Srila Prabhupada Memories #71