Behaving strangely, suddenly,

[Shaneyboy]

Have a car that all of the sudden is acting skittish. Was born in house and had always been friendly. Wife and i returned from town and feed them, ( other cats are brothers and sisters). After eating got to looking for him searched every where. Finally found him hiding in a dark closet and acting scared. Especially towards me. Will come to wife with caution, looks wide eyed at me and backs away fearfully. Not two hours before was sitting in my lap. Acted like he didn't even know us and like everything was new to him. Hour later he's acting normal again.

 

[Margot Lane]

Had you been anywhere new accumulating unfamiliar odors on your body? Worn a strange hat? Was there recent lightening? Is your cat getting old w/ personality changes or hearing loss? Been exposed to strange visitors? It’s a puzzler for sure but cats certainly have their own sensitivity to things. Very glad to hear things have returned to normal!

 

[Mamanyt1953]

There are two things we know for sure... First, something spooked him, and second, he can't tell you what it was. The main thing right now is that he has gotten over whatever it was, and it might well have been a smell you picked up outside. Or it could have been something that he heard, and somehow associated with you.

Should it happen again, try sitting on the floor with him, and allowing him to approach you. Remember how ENORMOUS you look to him when standing over him. Cats trust us more than we can ever know, to allow us to walk up to them.

 

[swampmonster]

When my cat Gimli was young something happened to him to make him very afraid of wearing his collar. I'll never know what it was. He had been wearing one since late kitten hood and then one day I come home and it's off. I tried to put it back on and he flipped. Near as I can tell it got hooked on something, thankfully it was a breakaway (I suggest nothing but these collars) he managed to escape but developed a phobia of collars for the rest of his days. It's a shame as he was quite dapper in them.
Your cat might've experienced a traumatic event while you were away. Maybe something fell near it, or a loud construction sound outside shocked it out of a deep sleep. Have you had maintenance people in? Do you rent and have a landlord who can access your apartment?
If you can rule out any random person being in your home upsetting your cat, then it could've been an isolated incident beyond your control. If it happens again, I'd take kitty to the vet to rule out any possible medical cause. Some cats who are in pain will associate it with owners or other cats because they don't understand what's happening to them.