Oh yeah. It's not even that strange either: we have an innate instinct to copy each other cos back in cro magnon days that's how we would've survived. The human is one of the very few mammals stupid enough to walk around with our delicate, soft abdomen exposed to any waiting predator. The herd thing is the compensation that enabled us to claw our way to the top of the evolutionary pile :-). Someone's running? Shit, must be a woolly mammoth! Quick! Let's ALL start running!
The Children's Crusade is a good historical example of mass hysteria. The Peasants Revolt started with isolated attacks on tax collectors in Kent before snowballing - Wat Tyler and Jack Straw came later (if the latter existed at all) and John Ball, who's often also credited, was actually in prison at the time.
Teenage girls seem especially vulnerable to mass hysteria, it's thought because of their higher ability for empathy and aptitude for rumination, untempered by the maturity of life experience. There's a school of thought that this may be why eating disorders are often so rampant in girls' boarding schools. Lisa Littman attributed ROGD to this phenom, too.
My favourite historical example is the Dancing Plague of 1518. It's a bit creepy though.
https://en.wikipedia.org/wiki/Dancing_plague_of_1518
I remember when Diana died. My initial emotions were shock, soon to be replaced by resentment that she'd gone and died on a Sunday and I'd have to cancel my plans and go to work. I was perfectly calm and composed, though. However, 14 hours of helping clients compose virtue-signalling public statements, against the backdrop of 24/7 news blaring out (the Americans, when they came on air, were even worse if anything) and I was an tearful, overwrought nervous wreck.