Magical powers were once thought to 'be attached to' the stone. [=the stone was once thought to have magical powers]
Little credibility 'was attached to' his story. [=people did not think that his story was very credible]
The shy child 'attached' herself 'to' her mother [=stayed close to her mother] during the whole party.
(..) Once he feasts on five souls, the sky will bleed again, and the abomination... will rise from hell. This is insane. This "thing" is attached to Mia's soul like a leech. It's becoming her. If we wanna stop this, if we want to help Mia... I think we gonna have to kill her. (..)2013 Evil Dead