Most baby animals are cute, but the change from caterpillar to butterfly is kind of gross. First, the caterpillar eats nonstop, and grows really fast for about 2 weeks, weighing 200 times as much by the end of it! Then it hangs onto a tree branch and sheds its outer skin, leaving a harder skin called a "chrysalis." Over 2 more weeks, the caterpillar's body turns into goop and re-forms into a butterfly. Finally the butterfly crawls out and pops open its wings. A lot prettier than the goop it came from!