Gerion staggers back confused. That last swing of the sword should have lopped half of the cactus' arm from it's trunk, yet somehow it just bent out of the way. Could the entire beast be an illusion of some kind?
Gerion pulls back, using his greater speed to get clear of the thing and gain a moment to think.
(Full: Withdraw action, back up to 80N20E then up to 10N10E, also hope to gain a disbelief save against any possible illusion now that he's interacted with it - quite painfully)
(Interpretation question - is Gerion truely missing entirely, or bouncing off of hard exterior? If missing entirely, this is fuelling the disbelief.)
(Man, I'm going to have to look up the stats for this thing once the fight is over. I'm as confused as Gerion, which makes me glad I *haven't* looked at the stats, 'cause it's more fun.)