Chess Opening Theory/1. e4/1...e5/2. Nf3/2...c5/3. Nxe5/3...f6

3...f6?
This natural looking move appears to eventually regain the pawn, but completely loses to 4. Qh5+!, and when black responds with 4...g6, White has 5. Nxg6!! and then, after 5...hxg6, there is 6. Qxh8, winning the rook.

'''1. e4 e5 2. Nf3 c5? 3. Nxe5! f6?