make an occasional sth.(model is used with nouns: This 5-foot apeman 'moved and sounded like a human, yet it wasn't'. It moved slowly past, making an occasional 'hoo' noise, and had obviously not noticed the mycologist lurking close by. (Janet & Colin Bord, "Unexplained Mysteries of The 20th Century")ART Vancouver)
pop up on occasion(Stories pop up on occasion of people claiming to be from a different time, like the alleged time traveller John Titor from 2036 and his scary warnings of a civil war in the U.S.ART Vancouver)
