Heavy artillery not an option?

I'd go with 'ignore' and perhaps someone else will pop up with recs.

Oh, just ignore. Not malicious, just someone having fun.

Malicious, perhaps not. Stupid and incorrect, and a waste of time, yes. The problem with that kind of joke is it doesn't factor in the mood of the person it's intended for. And given I've dealt with similar replies on coding boards that were malicious, my tolerance is quite low.