Inclusion Criteria:  Child virgin with experience for targeted acts during the 1st painful act or child undergoing follow-up provided that he is virgin with experience of the presence of clowns during these acts. Child with cancer Child requiring a painful act among the following 3 acts: lumbar puncture, myelogram, needle placement in an implantable chamber Parental authority holder (s) who have received full information on the organization of the research and who have given their written consent for the participation of their child Personal adhesion of the child with a view to his participation Presence of at least one of the two parents during act 1 Availability of the duo of clowns for the realization of act n ° 1 if the group assigned is the group Clowns-Sans Clowns  Exclusion Criteria:  Parents / child's refusal of clowns to intervene