Obsessive compulsive shadow chasing

by Hal
(Santa Clara)

My Coton is 14 weeks old and has been obsessively chasing his own shadow. We have noticed his change in behavior since this week. He furiously barks at his shadow and digs whether he is indoors or outdoors. When he gets into this "zone", stopping him is impossible as he totally ignores all attempts to distract him. This shadow chasing behavior has become really all he does.

We have tried redirecting his behavior by giving him Kong and other interactive food puzzles filled with peanut butter. We also have tried toys. Both of these options seem to work only temporarily. The only options that seem to help him snap out of the "spell" is if we pick him up/hold him or take him out for a walk.
Anyone else experience this obsessive compulsive shadow chasing behavior with their Coton and how did you solve it? Short of consulting a dog behaviorist, I don't know what else to do!