Hi Shelia.
The important thing to remember here is that children act how they feel. Period. Now, not judging their actions as 'good' or 'bad' can be a challenge, but when you look at it in this context it helps.
So---what is causing this behavior? I see this as a 2 part drama.
Part one:
Does he actually want the toy? No. Does he want to harm the other child? Not really. What does he really want/need?
It seems like he is doing a very typical and healthy thing for a 2 year old to do---he is feeling his own autonomy, his own power, and is asserting himself. He wants dominance. Healthy, normal, development. Establishing pecking order is part of human nature. I'll bet he doesn't do this to another child that might deck him! So part one is not really a problem. Children usually work this out on their own. How we respond to it can be--which leads us to part two.
Part two:
When he MUST have the toy, he wants dominance. When he asserts this wish and gains eye contact/attention from an adult, his desire is granted and fed. He gained dominance for attention as well. A bonus prize! Attention form a beloved adult is the ultimate reward. Especially when diverted from the child he was annoying in the first place. So this behavior is being reinforced every time the other child is 'rescued' and the cycle repeats itself. The attention he gains is worth asserting himself even more and aggression begins to take hold. He needs a "fix", the attention is the high.
My suggestion is to try and diffuse this situation before it happens. Of course he needs to learn boundaries and that it is not acceptable to hurt other children, but since he acts how he feels, his needs must be anticipated and met.
First-Next time this behavior happens, notice what happened immediately preceding the incident. What time of day is it? Is he tired? It the room noisy and overstimulating? Did someone just snatch something from him? What was he doing just before he decided he HAD to have this toy? Write down your observations and you will begin to see a pattern emerge. You are looking for triggers, then you can take steps to avoid them.
Second-Find something positive to praise him for BEFORE the behavior happens. Notice how well he is playing/sharing/coloring etc. and really let him know how special you think he is. He needs/wants attention, so give it to him! At the appropriate time and place. This will help diffuse the need to create a drama in the first place. This phase won't last forever. The lessons you teach in love and respect are worth the time invested.
Third-The behavior must not be rewarded with attention. Divert your attention from him when the behavior happens. No judgement, no anger. Just take a deep breath and relax yourself, focus on soothing the 'wronged' child, and then go about your business. No big deal. Hopefully he will be just standing there with (in his mind) this dumb toy in his hand and no one is paying any mind to it at all. Don't tell him to give it back, you are feeding into it. Don't over do it soothing the other child either, ill will on his part and helplesness on the part of the child will insue. This should resolve the problem within a few weeks.
If he is actually hurting the other child, the process is the same, but in step 3 above:
1. Take a deep breath and relax--this is important.
2. Pick him up and remove him from the situation. No emotion at all. No anger, no judgement. Just remove him to make the other child safe.
3. Tell him " I can't let you hurt the baby"
Repeat this over, and over, and over. He will tire of it. Not before you do (!), but he will tire of it. It is not worth his time if he gets nothing out of it.
I hope this helps. Please write back and let me know.
Blessings and best of luck!
L.