A small, unassuming plant in the corner of the level has nothing to draw your attention besides the open space around it. By clicking on it however, you can gradually grow the Beanstalk up to its full (off-screen) height.
Once it's fully grown, a person (presumably Jack) will peak out from behind then climb up the stalk. A second later, he drops down a treasure chest awarding you 150 gold.
FEE-FI-FO-FUM! Grow the beanstalk to the clouds!
- Jack and the Beanstalk is an old English fairytale. Jack sells a cow for some 'magic beans' which grow into a beanstalk that goes up past the clouds. He climbs it, and finds a Giant's castle. He steals gold and other treasures from the Giant before being chased back down the stalk, only for his mother to cut it down with an axe preventing, or killing the Giant who is chasing the boy.