Answer:
What do you get when you cross a pig with a karate expert?
What kind of coat can only be put on when wet?
I give people a huge fright but at the end I'm sweet. I normally celebrate at night when there's less heat.
I am all around you but you cannot see me. I have no throat but you can hear me. Valued during summer but despised in the winter.
I am black within and red without With four corners round about.
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.