My dog, Rico, has only ever done this when we had other dogs in the house.
First we had Lola and Rico, and he got along with her, playing with her, laying with her, but when it came to food, toys, and treats, he went into, what we call, "Flavor-Saver Mode."
Lola was very food-driven and would always eat as fast as possible, and Rico wouldn't touch his food until he knew she had finished her bowl, just so he could then eat it as slowly as possible in front of her while she barked at him.
He'd do the same with toys, grabbing a toy she had or knew she wanted, only to not play with it and just lay there while she barked at him because he had the toy she wanted.
After Lola was no longer with us, he did grieve for a while and he stopped doing this, eating at a normal pace, taking his treats normally, and playing with his toys instead of just hoarding them.
We got a new dog recently, Bandit, and Rico is back in Flavor-Savor Mode and, what we think anyway, is intentionally trying to bait Bandit into fighting so he has an excuse to snap or yelp.
He's eating slow and staring the other dog down, he intentionally positions himself in such a way that Bandit (who is bigger) accidentally steps on his tail so he can turn around and snap at him
And just now, Bandit was laying down, minding his business, and Rico came over with his toy, set it down in front of him, then started growling because Bandit was too close to his toy
YOU walked over to HIM, sir 🤨 you can't get mad that he's over here
It very much feels like jealously and like when older kids try to get their younger siblings in trouble
But he also did these things with Lola, and we had her before we got Rico
And he's not a violent dog, he's super sweet and well behaved, I just think he likes to be the victim so he gets extra attention. He never attacks Bandit, he doesn't bare his teeth, he doesn't whale-eye at him, he doesn't stress lick his lips, his hackles are never raised. He's even tried to play with him genuinely a couple times (Bandit doesn't know how to play), and he'll snuggle up next to him sometimes
Rico just also likes to try to get Bandit in trouble and bait him into starting something.
Is he just a jerk or is there a reason he does all this?