ur: a contraction formed by the pronouns we or you and the verb are; "Where ur going, Mommy?"(are you); "Ur going to Target after naptime." (we are)
whobody: pronoun used when you don't know who the person is you are referring to; can be singular or plural. "Whobody going to cut down that tree, Mommy?" "We are going to give that candy to whobody." "Whobody's car is that?"
Go on, try them out. You might find them to be quite helpful! We've certainly caught ourselves starting to use them :).