Two years ago, when cycling in India, several of our party were attacked by a swarm of bees. We were spread out over several miles while descending the Western Ghats into Kerala.
On my own, I stopped to take a photo of the amazing view and soon noticed a pesky bumblebee sized bee buzzing round. All of a sudden there were several of them and it wasn't long before I was being stung all over. I ran away (stupidly away from my bike) and started to panic. There was no one else around and I was being stung on my head, face, neck and through my (thin) shirt. I've never been so frightened in my life.
I ran back to my bike thinking I could out run them and gingerly rode further down the hill while swatting furiously and thinking about anaphylactic shock. I soon came across another of our party with blood all over him as he'd crashed his bike when attacked. For some reason the bees ignored his wife and she'd killed around 40 on him and dispatched at least that amount who were still over me.
Around half an hour later when we'd all calmed down, our back-up vehicle appeared and we got taken to the nearest town where others of our party had already arrived. Several other people had a been attacked and one other had crashed to the point where he was lying nearly unconscious in the middle of the road. A passing truck had ignored him through fear of the bees and he forced himself back on the bike to get away.
Aside from cuts and bruises (and the odd stitch in one case), we all felt fine once most of the stings had been removed and I assume the bees were an aggressive but fairly harmless variety? Horrible experience though.