he probably reacted quickly thinking you blundered! someone tried that on me and he said oops as if he made a mistake, I fell for it but then it turns out it wasn't legal's mate (no checkmate) it just looked like it, so I won the game with my queen. I didn't know about it at that time though.
Legall's Mate

Definitely. If he saw the trap he would have been up a piece. I exposed the queen knowing this too. Hoping he would take the bait. And boy did he bite.
Boog.
Definitely. If he saw the trap he would have been up a piece. I exposed the queen knowing this too. Hoping he would take the bait. And boy did he bite.
Boog.
You're absolutely right, however this is worth knowing for two reasons (other than recognizing it in order to avoid it)
1. sometimes, when black plays d6 instead of Nc6 and has not played Nf6, the move is completely playable, where if black realizes what is going on and takes the knight, white's queen can take the then naked bishop on g5
2. once in a while you may find yourself in a blitz game gone wrong and you'll have the stuff in place for this as a last ditch attempt.

If black had played 6...Nxe5 he would have won a piece. 7.Be2, Bxe2; 8.Qxe2, Nc6. It's usually dangerous to go for legall's if black has a knight on c6 although I think I've seen some games where it's playable. Here matters are made a little worse by the en pris bishop on c4 though and the fact that f3 isn't available.
I actually pulled off a Legall's Mate to a decently rated player. I guess the tempting Queen was too much to pass up. I was aiming for the Franco-Hiva Gambit. If you like gambits please join the Gambit Gang. We talk everything Gambit!!!
http://www.chess.com/groups/home/gambit-gang