Allie Garfinkle / Fortune : Mytra, which is building autonomous robots for warehouses that can move loads up to 3,000 pounds, raised a $120M Series C led by Avenir Growth —  Senior Finance Reporter And Author Of Term Sheet  —  Mytra's Chris Walti (L) and Ahmad Baitalmal (R).MYTRA  —  Chris Walti once led engineering for Tesla's humanoid Optimus.