The present invention relates to a deformable device (10), including a first thermoplastic material (40), said first material being substantially rigid at a temperature lower than a first threshold (T1) and malleable at a temperature higher than said first threshold (T1), said first threshold (T1) preferably being comprised between 40° C. and 90° C. The device includes an outer shell (16) made of at least one second flexible material (42), said outer shell defining an inner recess (18), the first material (40) filling the inner recess, the at least one second flexible material (42) forming the outer shell being in solid state at least until a second temperature threshold (T2) higher than the first threshold (T1) by 10° C., preferably by 20° C.