H.1.
My son had night terrors from around the age of 11 months on. I have talked to his pedi about this (I had even video taped one such night terror to show the doc) and he confirmed these can happen in babies and that's what it appeared to be. When Henry has a night terror - he is very confused - almost like he looks right through you and is desperate to turn his head away from you. I recommend looking into this to see if it fits the description of what your son is doing.
Caution against letting him get over-tired. This can lead to waking from naps or night sleep in a stage of sleep that makes him feel really "freaked out." Make sure he's getting enough sleep and try earlier bedtimes when his naps are ruined.