 CONT: It seems as if Mike was the last to join the seven back in the  1960s. The day Mike joins them was apparently several days after the  other kids had encountered It. Out of the discussion about It, which  takes place the day of the Rock Battle, we learn that every single  kid in the gang has already seen It somewhere. However, later in the  movie, Bev tells a story about the blood in her bathroom, and in the  flashback, we see all of the 7 kids entering Bevs bathroom to clean  the mess up, the day right after the blood had come out of the  washbasin.