My 1.5 year-old is terrorizing his daycare - what do I do?

My 19 month old son has some temper issues.Twice in the last 2 weeks, my daycare lady has pulled me aside to tell me that my son, who is the youngest of about 5 kids at daycare (max age almost 3) regularly hits, pushes, pulls at, and steals toys from all the other kids. He apparently pulled down a 2 yo boy the size of a 4 yo all the way to the ground and the kid hit his head on something. Not good.They have been putting him on time-outs, 2-3 times a day. It has not done anything to change his behavior.Most of the time when he takes a toy from someone and they catch him, they order him to give it back and he complies without issue. He then will usually grin and clap for himself for doing such a good thing. =/Today, daycare lady said that he has stopped listening when they tell him to give stuff back or do anything. He is getting worse and throwing fits more and more when he gets scolded. Example she gave today: the kids were all drawing, he wanted to hold a bunch of markers at once, they told him only one at a time, he threw a maaaassive tantrum.She wants us to be "working on his behavior at home," but I'm not sure how. He is much better behaved at home. When we have playdates with other kids, he never hits them or steals their toys. And if he ever did, we would never just let him do it without discipline. (Note: we don't spank, and we have not yet done timeouts - I have doubts about their effectiveness at this age.)Some things we HAVE seen at home that are troubling: as soon as we say the words "no" or "don't" or "stop," even if it's not in a stern voice, he starts either crying (normal, I guess), hitting himself with his fist, banging his head on floor, wall, or crib, or dramatically throwing himself on the floor (also common?). Or a combination of those. He also says "Ouch! Ouch!" as he does the self-harming behavior. It is unclear whether it actually hurts him or that's all for show, but I think he mainly wants a reaction and attention. He has been hitting himself like that in frustration/protest since before he was a year old.This does not mean we back off - we are firm and consistent, as much as we can be. Aside from protecting our own bodies when he hits, we tell him in simple terms and a stern tone, "No, hitting is not okay, hitting hurts," and that's it. We then dont reward the behavior with anymore attention as long as he's not damaging anything/anybody.We received advice to ignore the tantrums and just look or walk away and later praise him when he is showing good behavior. This has not shown noticeable improvement yet.So...what do I do? Is this under the realm of normal toddler behavior, or is it going too far? Is he a sociopath? It feels like my daycare is saying he's the only toddler who ever does this stuff. I hate that he's hurting other kids, and I don't know what to do about "working on it" if I don't see it happening.Anticipating some questions I might get:We (parents) do not hit each other or argue heatedly in front of son.Son is pretty verbal, has at least 75 words. Has very good receptive language skills - understands most things we tell him. It is mainly his behavior and social skills I worry about.He has been at this daycare since he was 3.5 months old and never protests going there. He seems to like everybody. When he's not doing the bad stuff, he is very sweet and social. via /r/Parenting http://ift.tt/2dflbv1