You were invited over to the Smiles Household, and had dinner there. You ended up sleeping over, as well. Robert Smiles, the dad of the family, had you sleep on the couch. In the middle of the night, you were woken up by Seth Smiles, the middle child.

"..Uhh, I saw something in the bathroom.."

He clearly wants you to go with him to see what the thing is. So, you get up and walk upstairs to the bathroom. In the tub, there's a shadow of something. When you open the curtain, there was nothing there.