Gerald Samson

Gerald Samson (better known as "Baby Gerald" or "The Monobrow (or Unibrow) Baby") is Maggie's arch-nemesis. He has a unibrow (hence his nickname).

Biography
Born on the same day as Maggie Simpson, the grossly underfunded Springfield General Hospital had one diaper left, and it was given to Maggie. Baby Gerald was wrapped in the discount section of the Springfield Shopper. Though known for its great deals, the coupon section is not known for its absorbency, and Gerald developed a terrible rash which persists to this day. He blames Maggie for this uncomfortable condition and spends his nap times plotting revenge.

Lisa has referred to Baby Gerald as Maggie’s rival. Gerald is distinguished by his unibrow, being one of the few characters in the show to have one.

On a few occasions, Gerald has been shown being pushed in a stroller by his mother outside the Simpsons’ house, with the two babies glaring at each other, the camera focusing on their narrowed stares. Homer often mistakes Maggie for Baby Gerald.

Gerald apparently has a history of causing large scale public incidents and was once rescued from an unspecified disaster by Bart’s mail order “wonder dog” Laddie. Both dog and baby were participants in a ceremony presided over by Mayor Quimby, during which the mayor inquired, "Baby Gerald, we can't help but wonder what mischief you'll get into next".

Physical appearance
Gerald is kind of a chubby baby (like many Springfield's babies) with a wide black unibrow (his main distinctive feature), a big wide nose, two big teeth, little hair (his neck hair is cleared out until the top of his head, his only piece of hair being a spiral) and a sky-blue baby's dress (lighter than Maggie's), like his bonnet. notes:1) his neck hair is visible in the longest daycare. 2) Gerald also have dresses made out of different colors than his original sky-blue, for instance a purple one.

Future
It is revealed that Maggie and Baby Gerald stopped being enemies, got married, and even had a baby together. The baby was named Margaret "Maggie", Jr. after her mother.

Trivia

 * In the new Simpsons sequence, when Marge goes to the super market, it shows Maggie shaking her fist at Baby Gerald.
 * Baby Gerald's last name was seen in a label of the Simpsons.
 * He is voiced by Joe Alaskey (Despite not even talking).