I saw a butterfly get stuck to a web once. It immediately started hurling itself violently away, trying to shake itself free. The spider was not immediately in

I saw a butterfly get stuck to a web once. It immediately started hurling itself violently away, trying to shake itself free. The spider was not immediately in evidence. I managed to take the web off it, but not without tearing off the part of the wing that made contact. I assume that in the butterfly's best-case scenario, that would have happened anyway. It was able to fly afterwards.