One Piece — "Basically, he's a monster."

From Volume 17 - Chapter 146 / Season 2 Episode 87. Being chased around by Luffy and Sanji, Chopper heard them calling him a monster, just like every other human. So imagine his confusion when they start chasing him again, begging him to join the crew. It's not until Wapol climbs to the castle and gets walloped by Luffy's rubber powers that Chopper finds out what the word "monster" means to the Straw Hat Pirates.