An amidautlus is a cluster of bubbles typically formed while one is blowing bubbles. Clusters of bubbles created and attached to a surface are not true amidautluses. The true amidautlus must be airborn and free-floating.

example: http://fc83.deviantart.com/fs32/f/2008/188/1/e/Bubble_Cluster_by_regularjane.jpg