Nurse, M&M, and Monkey Puns

Listen up, buttercup. The nurse is gonna draw blood, but instead of using a needle, she uses a red pen. Get it? "Draw" blood, like drawing on paper. As for the M\&M, it wants to be a "smartie," like the candy. And the monkey? It wants to be in "highschool" by using a ladder to get up high. These are all puns, which is like, the lowest form of comedy, which is probably why you think it's funny.