### Clue: Alien surrounded by crowd in joint (7)
### Answer: FETLOCK 
 ### Explanation: Definition: joint
An envelope ('surrounded by') of ET (the extraterrestrial of the film, 'alien') in FLOCK ('crowd'). FETLOCK is a tuft of hair above a horse's hoof, or the joint in that area between the cannon bone and the pastern (the shinbone and the ankle, approximately).