Asteroids and comets formed on opposite sides of the snow-line. They convey to us information about substantially different radial distances in the protoplanetary disk of the Sun. We have recently discovered strange hybrid objects which orbit in the asteroid belt but whose properties are those of comets (from the much more distant and icy Kuiper belt). I will describe these new objects and discuss what they tell us about the origin of the oceans and about dust production in the solar system.