Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nf6/4. Ng5/4...Bc5/5. Bxf7/5...Ke7/6. Bd5/6...Rf8/7. O-O/7...d6/8. c3/8...Bg4

=Traxler Counterattack=

8... Bg4 Threatens the White Queen but also the f3 square as one possibility for Black is to find a weakness in the light squares around Black's King.

Theory table
.
 * 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 Bc5 5. Bxf7+ Ke7 6. Bd5 Rf8 7. O-O d6 8. c3 Bg4