Mindy is a girl who was killed by Horribus during the 2002 Halloween Party[1].
Like all who die in Brie Meighsaton house, her ghost is trapped by Kesandru's spells. However, her spirit does not manifest before the housemates until the house is pulled to the Never, at which time she grabs on to Beth (who is holding on to Sam, whose spirit is still bound to his undead flesh) in order to avoid being pulled into the Well of Ghosts[2].
When Godhounds attack the house, Mindy is ripped apart and mostly devoured. The only remaining part of her is her head, which Torg places in the Well of Ghosts. When Wilbur pierces the veil to send the spirits home, Mindy is released along with the other ghosts[3].