Visible crew/equipment: In the garage scene, Drake hands Josh the baby to see if the baby needs changing. After Josh has sniffed the baby, he falls backwards onto the floor. The black crash mat that he lands on can momentarily be seen in the bottom-left hand corner of the screen.
Continuity mistake: When Drake and Josh are trying to pull the phone from the base, the phone gets thrown across the room into the fish tank and breaks. Then about two scenes later the phone and base are back on the table and fixed up.
Revealing mistake: When Josh lets go of the gutter and falls on Walter's boss, if you look closely and watch as Josh falls on top of him, it's a dummy in Josh's clothes. The dummy is much lighter than Josh was at the time and its ankle twists backward.
Chosen answer: It's just a screaming fan that knows everything about Drake.
BigOLB