This is the Jaws theme.

Start out slow playing this.
G: -------------------------------------
D: -------------------------------------
A: -------------------------------------
E: -3-4-3-4-3-4-3-4---------------------

Play this after you speed up.
G: -------------------------------------
D: -------------------------------------
A: -------------------------------------
E: -3-4-3-4-3-4-3-4-3-4-0-3-3-4-0-3-3-4-

When the person gets attacked:
G: -14-14-14-14-------------------------
D: -------------------------------------
A: -------------------------------------
E: -------------------------------------