Järnpojke (Iron Boy), is Stockholm's smallest statue at 15 centimeters high. Tucked away behind the Finnish Church on Gamla Stan, the belief is the boy has magical powers prompting visitors to leave coins or candy at his feet and stroke the top of his head.

Sometimes in winter he even sports a knit cap

Other superstitions according to Wikipedia:

Who runs 3 times around the sculpture counterclockwise comes certainly will be back to Stockholm.
Who strokes head of the sculpture 3-times and makes a wish, the wish will come true in a year.
Who leaves the sculpture a treat (money or candy), in the same year will have an addition to the family.

I really wish I had known that last one... I guess we'll be getting a new four-legged member!