17. Bd3
*gulp*
I wouldn't really call this a pin; it's more like an "anti-discovery". I can't capture the grasshopper because its move "anti-discovered" a check from another grasshopper. There's certainly no equivalent tactic in normal chess, but I'd say the closest relative is probably the ordinary discovery...
...says the guy getting utterly destroyed at a game he claims to understand. Ah, well...
22. Kf2
You're right, a discovered check (or anti-discovered) is a better name for it. I had to think if there was an equivalent tactic in normal chess - and I agree - seems to not be one.
22...Gg1
24. Bxg5
It seems you've completely outplayed me in this game, so well done. Barring an unimaginable mishap of some sort, Black should now win easily.
16...Nd4