[2D] Player's arm following the mouse

So as the titles says I want the players arm to pivot on his shoulder so the hand points towards the mouse. LookAt doesn’t work because it tries to change the z-Axis which makes the sprite disappear I’ve tried other methods but can’t quite figure it out.

a work around would be to after using look at move the value from z to the proper one. but that may still have issues with being the right angle. best way i know of would be to calculate the angle needed yourself. you have the x/y pos of the mouse as one point, and the x/y of the arm as a second. the straight line between the 2 points would be the hypotenuse of a right triangle, from there it’s just a little bit of trig to get what you want.