Mule

JESS: Hey. Your mom home?
RORY: I’m bringing supplies [carrying take out bags].
JESS: Should’ve brought a mule.
RORY: What?
JESS: A pack mule, to carry it.

Mule, a domesticated hybrid between a donkey and horse, the offspring of a male donkey (a jack) and a female horse (a mare). Mules vary widely in size, and may be of any color. They are more patient, hardier and longer-lived than horses, and are perceived as less obstinate and more intelligent than donkeys.

There is a comic misunderstanding here where Jess suggests that Rory get a mule if her mother is hungry, which Rory takes to be a rude comment that Lorelai is so greedy she would eat an entire mule! Jess quickly explains that he meant she should get a pack mule, to carry all the food (which is still a little rude, implying that Rory has bought a huge amount of food). Mules make good good pack animals, as they can bear heavy weights.