He tends to pop up like a bad penny when you least expect him.
Он имеет привычку неожиданно появляться, как плохая копейка, когда его меньше всего ждешь.
Definitions
To appear or turn up repeatedly and unexpectedly, especially when not wanted or welcome. The phrase suggests someone or something unwelcome keeps reappearing, much like a 'bad penny' that always seems to come back into circulation.
