The AoO will obviously be a tail slap.
"Coward!"
Although Gol can't see Fang now, he will soon enough. Fang moves south to 20n50e and casts a spell. The area north of Fang, a cylinder 20ft high with a radius of 40ft, centered at 80n60e, fills with blinding sleet. This storm extends out over the water and outside of the VZ.
Once Gol can see Fang again, he'll see the sharp-toothed dragon motioning him down with a claw.