Ethan is absolutely terrified of them. Even the small ones send him running to his "safe spots" to shiver in fright.
Skylar is only afraid of the larger ones, and all he wants to do is sit in someone's lap and bury his head in their arms.
Frisk doesn't even act like he notices them as long as he's with someone. If he's alone on the sunroom or something, he'll come running to me as if he's asking me if I know there is a storm here^^. Then he calms down.
The cats appear to ignore them.