Continuity mistake: When we first see Sherry's Mustang, it has a black convertible top, but later in the film when she and Big Momma ride into town the top is now white. (00:04:35 - 00:18:25)
Other mistake: When Big Momma is taking a shower, you can clearly see that the shower head is a mirror, with the water coming only out of the top, and when Big Momma bends over, you can also see her reflection in the shower head. (00:12:00)
Visible crew/equipment: When they are making the face of big momma we see the camera pass Malcom's back and then out again. When it reaches the other side you can a cameraman with a beard watching him in the mirror just before the other guy walks into the room. (00:17:00)
Continuity mistake: When Martin Lawrence tears the face mask and puts duct tape over it while cooking, it disappears when Mr. Roy comes for a visit just a few minutes later. (00:22:00 - 00:25:30)
Continuity mistake: Big Momma and the girl are in the kitchen and Big Momma tapes her face. In the next shot, no tape. (00:23:10)
Continuity mistake: When Big Momma's gentleman caller comes the door, Martin Lawrence takes out his gun and goes to answer the door. His gun is still in his hand up until the point when he answers the door. As soon as the door opens, the gun disappears. (00:25:20)
Continuity mistake: In the scene where Big Momma's gentleman caller comes to the door, Martin Lawrence runs over to the door and stands directly in front of it with both of his hands up gripping his gun. This can be seen in the shot when we see into the house through the window on the door. In the very next shot both of his hands are down. (00:25:25)
Factual error: In the movie, when the baby is born and Big Momma delivers it, the baby comes out without any blood and there's no umbilical cord. (00:34:20)
Continuity mistake: The sun was high in the sky at 5:45 a.m. I've lived in GA all my life and the sun has never been that bright at 5:45 a.m. (00:36:55)
Continuity mistake: When Big Momma wakes up to find that his face is peeling off and Shari knocks on the door, Big Momma goes out the window and his whole outfit comes off. He is completely dressed in a T shirt, sweats and tennis shoes. Why would he have clothes on under Big Momma's outfit, it would be too hot. (00:37:55)
Continuity mistake: When Martin rips the door bell off the door, throughout the scene it changes from wires hanging out with the door buzzer attached to just a bunch of wires. (00:38:55)
Continuity mistake: When Big Momma and Sherry park on the street in town the car they are in is a Mustang GT and when they get out and walk away the car is a Mustang LX. (00:42:10)
Continuity mistake: When Big Momma (Martin Lawrence) is in the place where Nolan supposedly teaches them to defend themselves. When Nolan is looking at Gertrude, you can clearly see a young face, with no wrinkles. Then when she is laying down on the floor, there is a very old face. They used a double for the scene in which she is hit. (00:43:20)
Continuity mistake: The sun was exactly as bright the evening they went fishing as it was at 5:45 a.m. (00:53:55)
Other mistake: When Nia Long and Martin Lawrence are sitting in the boat on the water, talking about Jascha Washington. You can see a fisherman in the background, but if you look close enough, you can see it's a fake person. (00:55:35)
Continuity mistake: Given that, the little boy chases fireflies (which don't light up until dusk). It was entirely too bright out for the fireflies to light up. (00:55:50)
Continuity mistake: Martin covers the girl with a blanket in the "evening" while the boy is chasing the fireflies. It is never cool enough in GA during the season of fireflies to warrant a blanket. Never. Unless there was some weird and unexplained weather phenomenon. (00:56:00)
Continuity mistake: When Malcolm finds the money he throw Sherri her necklace, but in the next shoot Malcolm is wearing the necklace. (01:17:10 - 01:20:15)
Other mistake: Near the end where the real Big Momma knocks over the 2 fighting guys and falls back on top of the security guards, and she's being held down, you can see what appears to be part of a fat suit coming from underneath her clothing. (01:26:50)
Continuity mistake: Near the end of the movie, Sherry and Malcolm are talking on the porch. Sherry, has a blanket wrapped around her. On her right shoulder you can see her skin. From an opposite angle when Malcolm's face is shown, her skin isn't visible. (01:28:55)
Answer: I think it's the toilet unclogging. Also, he was probably looking at the diarrhoea she left behind in the toilet bowl.