Cosmic jokes.
because the owner will tell you
I am the one who Knock-knocks.
Three. One to post it, another to post a better punchline in the comment section, and another to repost it with the new punchline.
Ouchwitz >say ouch when offended or in pain >Witz is the German word for joke >sounds like auschwitz
Tune a fish
Address.
Because they take a steroid.
Because you have to planet.