Why cant Monkey King enma move?

2 appearances of his, first one in a flashback where hiruzen lets orochimaru walk out, Enma is just lying on the floor asking hiruzen to kill orochimaru.

Second tim during orochimaru vs Hiruzen, hiruzen is fighting Orochimaru, he summons Enma, and most of the time, enma stays in one spot as a stick, towards the end when hiruzen tries to reaper death seal orochimaru, and is about to get stabbed by orochimaru sword, Enma transforms into a monkey and doesnt try to get up or anything, instead he is moving his hands and legs desperatley to try and grab the sword (while laying down), can he not get up or something?? He does have both of his legs, and he is standing on his legs in the flasbakc too, whyc cant he get up and grab the sword that was about to (and eventually did) stab hiruzen?