The skeleton and bat scream loudly, but soon, a different emotion comes over them.
"Thank you for lifting our curse!" they say calmly and gratefully.
"We were trapped by a dark seal on our fates. Since it was a powerful curse you've rescued us from, we can grant you one wish before the magic is spent; before we rest and return to our rightful places. Be warned: extravagant wishes may bind you to this house, as we were."

You think for a second. A few things come to mind. You could ask for:
Limitless wealth,
Fame,
Immortality,
World peace,
Your favourite candle from the previous room,
Knowledge of how to leave this house, or to be transported
Home.