I'm just a sucker for an elaborate visual pun. It is, of course, referring to the little ditty that grandparents recite while playing with kids' toes: "This little piggy went to market, this little piggy stayed home, this little piggy had roast beef, this little piggy had none, this little piggy cried 'Wee, wee, wee' all the way home."
And for those who don't know, Arby's is a fast food restaurant that specializes in roast beef sandwiches.