Super-Hobgoblin

So Neo (31 strength, blessed +7 +6 two-handed sword, etc) is on level 73 and needs to polymorph a dragon. Hooray, he's now a hobgoblin, heh heh.
Swing and a miss.
Swing and a miss.
Swing and a miss.
Over and over again.
He CANNOT be hit.
What's going on?
Swing and a miss.
Swing and a miss.
Swing and a miss.
Over and over again.
He CANNOT be hit.
What's going on?