Yo Mama is so fat that:

When she hauls ass she has to make two trips.
When she dances she makes the band skip.
When she was diagnosed with the flesh eating disease the
  doctor gave her 13 years to live.
She puts mayonnaise on aspirin.
Her ass has its own congressman.
When she goes to the zoo the elephants throw her peanuts.
Her high school graduation picture was an aerial photograph.
Her driver's license says "Picture continued on other side."
The back of her neck looks like a pack of hot dogs.
Yo mama's so fat, "Place Your Ad Here" is printed on each
  of her butt cheeks.
Yo mama's so fat, all the restaurants in town have signs that
 say:
"Maximum Occupancy: 240 Patrons OR Yo Mama"
Yo mama's so fat, when she ran away, they had to use all
four sides of the milk carton.
Yo mama's so fat, when she gets in an elevator, it HAS to go
 down.
Yo mama's so fat, she was born with a silver shovel in her mouth.
Yo mama's so fat, when I yell "Kool-Aid," she comes crashing
  through the wall.
Yo mama's so fat, she could sell shade.
Yo mama's so fat, when she crosses the street, cars look out for
her.
Yo mama's so fat, she gets runs in her jeans.
Yo mama's so fat, her blood type is Ragu.
Yo mama's so fat, when she goes to a restaurant, she doesn't get
a menu, she gets an estimate.
Yo mama's so fat, if she got her shoes shined, she'd have
to take his word for it!
Yo mama's so fat, she has to put her belt on with a boomerang.
Yo mama's so fat, when she turns around, people throw her a
 welcome back party.
 Yo mama's so fat, she can't even jump to a conclusion.
Yo mama's so fat, she went to the movies and sat next to
 everyone.
Yo mama's so fat, her belly button doesn't have lint, it has
sweaters.
Yo mama's so fat, her nickname is DAMN!