That's Grux trying to carry a stick that is longer than him. And he's trying to carry it vertically, so he keeps getting it jammed into the ground and he can't figure out why he keeps suddenly being stopped.
G has a major thing for sticks. He LOVES them. You can throw a toy and a stick for him and he will always go for the stick. Torture for G was watching me pick up a bunch of sticks one day after a storm and put them just outside the fence - he wanted those sticks! At least he's easy to please.