Is it a shark fin? Is it a loose tooth? No! It's a Rare 1985 Ibanez Axstar in excellent condition. Not a lot of info on these things. Not many were ever made and far fewer are still in existence.  Everything works great, plays and sounds awesome.  All original with original hard shell case.

Below is from myrareguitars.com :
In around 1985 Ibanez found its sales flattening out and needed something new to pep them up. The result was a new series called the Axstar. Two models were conceived, both to be made for them by Chushin in Japan, rather than the usual Fuji Gen Gakki. One was popularly called the “shark” because of its obviously finned shape. The other was this headless, commonly called the “battle axe,” designed in Bensalem, PA, by Ibanez’s then chief designer Mace Bailey.