Disney Pixar Monsters Inc I'm Your Boo Girls T-Shirt Mary, or Boo, is so cute even monsters can't help but love her! Join in the fun with the Monsters Inc. I'm Your Boo Juniors' T-Shirt! The lovable Boo is portrayed in her monster suit beside the phrase "I'm Your Boo" in white text down the front of this Monsters Inc. tee. Runs small, size up.