I'm guessing that the big problem is the starfish can be at any orientation when it tries to climb the glass. You don't know which arm will be trying to climb and the rotation of the starfish can be anywhere from 1-360 degrees.
What I would do, since the starfish moves so slowly, is create a scripted animation of the starfish climbing up onto the glass starting from the arm touching the glass all the way to the starfish being up on the glass. Let's say the rotation of the starfish at the beginning of the script is 30 degrees and at the end the starfish has rotated a little bit and so it's 45 degrees. So now you have your scripted animation which works well starting at 30 degrees.
Now we know that, if the starfish is in the "home" or 0 degrees position, then the arms are sticking out at 0, 72, 144, 216, and 288 degrees (I divided 360 degrees by five). Since our animation looks best when the starfish is rotated 30 degrees, then let's add 30 degrees to all those numbers. So we know that if the starfish is at 30, 102, 174, 246, or 318 degrees, you can start the scripted animation (which starts at 30 degrees) and it will be fairly seamless. Even better if you can do a morph at each end.
So the starfish is crawling along, one of the arms is at 30, 102, 174, 246, or 318 degrees. Bam, you can spin the starfish around to 30 degrees and then start the scripted animation. Then at the end of the scripted animation, the dictated rotation should be 45 degrees, so you'd resume the 'live' animation of the starfish with a setting of 45 degrees.
Clear as mud? Did that make any sense at all?
