This is definitely a bug - as indicated by the characteristic body form and the segmented (it should be five) antenna. My guess here is that this is Nezara viridula, also known as the "southern green stink bug" or the "southern green shield bug".
See this image (from here):
Looks like a common green stink bug - https://en.wikipedia.org/wiki/Green_stink_bug
Give it a test. If you put it into a handkerchief and scare it a little, it should give off a foul smelling odor