NotJustaBoy - not just a boy thing as everyone has said - but - it could be a bit of a youngest of several children thing.
Not that all youngests have this phase, nor exclusively youngests of course
but my older two are very close in age and then I have a bit of a gap (only 3.5 years but seemed like a huge gap when he was small), and the older two absolutely indulged him - he was the cutest toddler (not mum goggles obviously) with big long lashed eyes and longish blond hair and the cheekiest grin, always doing amusing things and striking poses...
He was ridiculously spoiled by his siblings more than us, but also he grew up hearing us telling his siblings that we were sorry DC3 had broken X or interrupted Y or made Z dirty, and we would do a better job of keeping him away, but he was only little and didn't understand and they were such good big brother and sister not to get cross with him and to always be so gentle with him... that of course he was naughty when he hit or pulled hair, but toddlers don't understand what they are doing the same way big children do (and he would say sorry and do the big eyes and they'd ask him for a cuddle and be friends again).
Backfired spectacularly for a while as DC3 always thought of himself as the cute little imp who couldn't actually hurt anyone or do any real harm. He got to 3 and 4 and actually could hurt his siblings, and was older than DC1 & 2 had been when the Big Sibling tolerance had been expected...
He never lashed out at preschool through luck more than judgement, but he also never had the older sibling's innate instinct to be gentle and tolerant with other kids. It took a long time to re-condition him to realise he no longer had a get out of jail free card!