How can I get past the guard dog in the Ogre's house

Hint 1 of 7:

That dog should not be a bonefied problem to you.

Hint 2 of 7:

(If the door is locked, you have not completed the unicorn problem.)

Hint 3 of 7:

Did you check behind any waterfalls recently?

Hint 4 of 7:

You would need to be a strong swimmer to get back there.

Hint 5 of 7:

Wear the frog prince's crown to swim behind the water fall.