Is this mate illegal or Legal?

I have been waiting for years for one. Apologies to my opponent, who no doubt took me for a fish (which is close enough to true).

Legal's Mate :D
Congrats!

Common trap, legal mate. Congrats.

I saw that on a stream lol. It's a good fun trap. Still waiting to manage to play it.

legal trap is more flexible than i tough. accept some variations it seems. gg

I have not ever played that before

nice!

Well, I'm 74 years old. You have lots of future time.

This has even a name. In Germany we call this the "Seekadettenmatt"
de.wikipedia.org/wiki/Seekadettenmatt
and it was mentioned in the very first chess book I read with about 10 years.

he could take on d5 and be better
i wouldn't risk it