One night at Jeffy's was an sml and fnaf fan game, which was owned by janmaar03 the game was about you being in the sml studio. There were three games made and released, which were One night at Jeffy's, One night at Jeffy's 2, and One week at Jeffy's (or One night at Jeffy's three), there was even a fourth game planned, but the creator deleted all of his games, even the ones that weren't in the one night at Jeffy's series. One night at Jeffy's, One night at Jeffy's 2 and One week at Jeffy's, have been partly found by old youtube videos, one night at Jeffy's also got a fan remake
One night at Jeffy's: partly found
One night at Jeffy's 2: partly found
One week at Jeffy's: found by a series of videos video1 video2 video3
update: I found the dead link to the 2nd game