A dog who is in the act of digging up your yard; A dog who is covered with mud and was obviously digging craters in your yard; the act of digging up someone's yard; digging up someone's yard with a 4 x 4 truck; doing cookies in someone's yard thus digging it up; creating any muddy mess in someone's yard in any way possible.
"Look at that, the dog is mudmoosing up the yard again." "Holy sh** stop that dog from mudmoosing up the yard!" "the kids have been mudmoosing up the yard with their dirt bikes." "I caught my x-boyfriend mudmoosing up my yard with his 4 x 4." "You stupid dog, stop mudmoosing up the yard!"
by Lars the Conqueror March 31, 2010