Clouds of atoms cooled to almost absolute zero can form a collective state--in effect, a giant atom--called a Bose-Einstein condensate (BEC). The stability of a BEC depends almost entirely on how the atoms making it up interact one-on-one, and collisions of ultracold atoms provide a glimpse of these interactions. In a first-ever detection, a group of researchers in Paris has gotten cesium atoms to form ordinary molecules chilled to 300 millionths of a kelvin--something only seen before with atoms--which could be the first step toward studying complex materials in the world of the ultracold.