"Okay Soph, show me the monster," Jack encouraged her. Jamie had flagged him down during a snowball fight earlier to tell him that Sophie had been talking about a monster under her bed, and she wouldn't sleep in her own room because she was too scared. Jamie was hoping Jack could help. Either there wasn't a monster, in which case Sophie would probably believe Jack more than Jamie or their mom, or there was, and Jack was more qualified to fight it than Jamie or their mom. Jack of course agreed.
Slowly, reluctantly, Sophie led the way to her room, but refused to go in, cowering nervously behind the door frame.
The room mostly seemed normal, until Jack bent down to check under the bed itself. He was not expecting the enormous jagged teeth that tried to take his face off.
"Whoa!" Jack reeled back with a cry. Then he shot a jet of magic under the bed, forcing the thing snarling out into the light. It was a huge, misshapen thing, bigger than should have logically fit in the space under the bed, with twisted limbs and burning eyes. It hissed and snapped at Jack, growing ever bigger as he watched.
Sophie screamed, bolting down the hallway. The thing made to follow her, but was stopped by the butt of Jack's staff slammed into the floor in front of it. It growled, hunching down and glancing back and forth between Jack and the door. Just as it was about to bolt, Jack struck, lashing out with his magic.
The fight was short and brutal. A snarl, teeth in his ankle, magic flying every which way, the monster losing one of its far too many limbs to a blast of ice. The monster, realizing it couldn't win, tried to make for the bed to hide again, and that gave Jack an opening to freeze it solid. Jack breathed for a moment. Then he hauled the frozen monster to the window and threw it out, leaving it to smash on the ground. He watched for a while, to see if it would reform the way some monsters had a bad habit of doing, but it melted into smoke. All the same, Jack took a moment to use the magic North had been teaching him to seal the window and ward the bed. Then he went to find Sophie.
She had ended up in the living room, hiding terrified behind the couch. Jamie was trying to coax her out, but she just shook her head, crying in fear. Jack crouched down next to Jamie with a gentle smile.
"Sophie," he called softly, "It's gone, you can come out. You're safe."
"Promise?" she sniffled.
"I promise," Jack vowed, "It's never going to bother you again."
She barreled out to be wrapped in a hug as Jack laughed in relief.