The Terenzi Brothers survived the explosion of their ice cream truck while still inside it when it was thrown by the big bad monster clown... they hid in the freezer with all the ice cream. After the spaceship exploded, the burned out truck fell at a great height, and they still managed to survive in one piece after all that!
The above troper clearly Took The Bad Film Seriously. It's a movie about alien clowns who wrap people in cotton candy cocoons and drink their blood through curly straws, man! Lighten up!
It's the Headscratchers page, it's the appropriate place on the wiki for it. I just saw the movie for the first time and was unaware it was a parody of monster movie tropes myself until I saw it.
They are clearly experienced rogues and simply made their Reflex save for zero damage.
The freezer walls were fireproof, shatterproof, and cushioned. These guys must love their ice cream.
Are the clowns actually wearing clown makeup, or is that their natural coloring?
According To A DVD Extra they're Space Slugs that Happen too look like Clowns So I'd Guess it's their natural coloring.
The Klown-spawn that sprout from the popcorn on Debbie's clothes are white-faced, and they certainly wouldn't have had access to make-up in her laundry hamper, so presumably they're born (hatched?) that way.