Perhaps a member of "false leaf" katydid subfamily Pseudophyllinae
Could be Phyllomimus sp, Cratioma sp, Hapalophyllum species or other flat body Pseudophyllinae.
Suplementary information, such as, location (continent, country, islands), wild-vs-captive bred insects, habitat (forest, garden, etc) will be helpful if there are members who wants to join the ID discussion.