Okay, so I don't know if I'd call it a straight up split personality. But that's what it feels like.
I have an eight month old neutered greyhound/lab cross who I've had since he was two months old. He's a very good dog; he was house trained early and learned to sit, shake and lie down early too. He likes strangers (although, he does jump up on them because he gets over excited) and he doesn't even mind car rides. He loves going on walks and chasing crows and he barks at threats until they're gone. He has constant access to water and is fed enough too, is played with and is walked daily and I treat him better than I treat myself, and though I barely have any money the majority of it is spent on him.
My dog likes to lick and play and he'll lick someone's face or hands for minutes at a time with such enthusiasm it's like we rolled around in his food. He chases his tail and he runs around and he plays with his toys ...
And then he starts jumping up on me and tries to bite me with absolutely no warning, when he was playing just a minute ago. And he viciously growls, wrinkles up his nose and continues jumping up, his jaws flailing as he tries to bite my hand and wrist and when he gets tired of that he goes for me feet and legs, growling and snapping the entire time.
Oh and sometimes when I bring him into my bedroom (which he's generally fine in, he sleeps on my bed) he'll start attacking me too. Whether I'm awake or asleep. He'll start snapping and growling and diving at me with an evil expression on his cute little face, looking like he wants to cause me actual harm.
I'm not afraid of him, I never cower away from him, I always try to discipline him vocally and by giving him a shove away from me when he dives at me, and holding him there until he calms down. But he doesn't
calm down. He just keeps going until he gets free and can attack again.
This dog can go from laying down on the end of my bed, casually licking his own paw, to diving at me and snapping in an instant.
Oh, and he frequently steals things he's already been told and shown he's not allowed to steal and he runs around the round kitchen table with them, or up and down across the bed with them until I manage to bribe what he stole away from him. The stealing and destroying things has gotten to the point where I can't even let him sleep with me every night anymore - only on nights where he isn't attacking or trying to destroy my pillows.
He's been doing all of this both before and after getting neutered, by the way, if anyone tries to attribute this behavior to that. He's always been like this, but it just keeps getting worse instead of better. And no, I can't afford a professional dog trainer if anyone suggests that. Most weeks I can't even afford to feed myself, so that's a definite impossibility. All I seek is advice or if anyone has had similar experiences.
Come to think of it, I would call it a straight up split personality. I don't understand this dog.