Toward the end of the boss fight against Serleena in Men In Black: Alien Crisis you will likely get caught by a tentacle and get eaten by Serleena and have to do the entire boss fight over again. How do you kill Serleena?
There is no way you can dodge her testicles, so you need to nail the process in stopping her from eating you. You need to shoot the leaf parts of the mouth. When she first pulls you into her mouth you will notice that there are 4 leafs like things around the mouth. Shoot any one of these and you will be dropped. The next time she grabs you, you will see that the leaf you shot in the past will be missing and you cannot shoot it anymore. You need to shoot all 4 of these leafs.
When i first did this fight i was just shooting the mouth and i guess i was getting lucky the first 3 times and was always hitting a leaf. When she picks you up the final time there will be only one leaf left around the mouth. Aim carefully and shoot this leaf and the battle will be over.
The Tri barrel is probably the best weapon for this as it has a much faster rate of fire compared to the other weapons. You are more likely to hit the leaf when you are shooting more bullets.