Omega!! Note: surely it already exists but I thought of it independently and am proud of my terrible joke!
Because he thought it was another mole, due to his poor eyesight.
The landlord at The Dog And Duck pub needed a new sign to hang above the door, so he contacted his signwriter. The signwriter arrived a week later with the new sign, hung it above the door, and asked the landlord what he thought. The landlord replied with, "I like it. However, I do feel that there should be bigger spaces between ' ' and ' ', and ' ' and ' '".
Zoos
Moose-saka
They think, therefore they arrrr
Because chickens didn't exist yet.
Prism (Note: I made this joke up. Sorry if this little note refracts from the humour.)
A pun is a play on words, while Cliff's notes are a word on plays
Karma. (Please forgive me)