Pygmy marmoset

https://packaged-media.redd.it/om6h8yx44e1h1/pb/m2-res_854p.mp4?m=DASHPlaylist.mpd&var=sgpssan&v=1&e=1779267600&s=cec3f00d0f6e1128b2b8343c933634db440a751b

Smallest true monkey. The average adult weighs about 3.5 ounces.