Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nf6/4. Ng5/4...Bc5/5. Nxf7/5...Bxf2/6. Kf1/6...Qe7/7. Nxh8

7. Nxh8
At the moment, White has a deceivingly uncoordinated attack on the Black king, but things can go very wrong very fast if Black allows moves like Bf7+ or Qh5+, preventing the Black king from ever castling to safety. For this reason, Black cannot afford a tempo moving their f2 bishop away or capturing with Nxe4. Instead, their best move is to cut off White's bishop with the move 7...d5.

This is not simply a free pawn, and leads to interesting offensive opportunities for Black.