Lance ("Launce" in some editions of the play) is Proteus's servant. When Proteus is sent to Milan, Lance is forced to go along. He's reluctant to leave his beloved dog, Crab, behind and somehow manages to take the little guy along with him.
Lance often appears before the audience and delivers silly monologues about his relationship with his beloved Crab. Check out Lance's description of what happened when Crab got caught "a pissing" under the Duke's Table:
all the chamber smelt him. 'Out with the dog!' says
one: 'What cur is that?' says another: 'Whip him
out' says the third: 'Hang him up' says the duke.
I, having been acquainted with the smell before,
knew it was Crab, and goes me to the fellow that
whips the dogs: 'Friend,' quoth I, 'you mean to whip
the dog?' 'Ay, marry, do I,' quoth he. 'You do him
the more wrong,' quoth I; ''twas I did the thing you
wot of.' He makes me no more ado, but whips me out
of the chamber. How many masters would do this for
his servant? (4.4.1)
Lance is not only funny and entertaining, but he's also incredibly loyal to his dog. Rather than allow Crab to be whipped, Lance takes the blame and a beating for supposedly wetting his pants. We also learn that Lance has endured other punishments for Crab's bad behavior. He stood in the stocks when Crab stole some "puddings" and he stood on a pillory when Crab killed a neighbor's geese (4.4.1). It seems like Lance's relationship with Crab is a parody of some of the romantic relationships in the play, don't you think? Like the loyal Julia, who follows Proteus to the ends of the earth and forgives his infidelity, Lance is completely devoted to his pooch.