When I first saw this ice cream treat, I thought it was dragon fruit flavoured. The package shows a white ice cream/Popsicle treat with little black dots, and since the wrapper was almost completely in Thai, I just assumed it was dragon fruit. At the time I was scouting out stores in Thailand for interesting cool treats. It piqued my interest enough that I went back to the 7-11 the next day to pick it up. Then, upon closer inspection I found some English writing and discovered it was a black bean ice cream treat. This made me even more interested, particularly since most of the dragon fruit I've eaten, while looking cool, is fairly bland flavour wise.
While I knew that the black specks were black beans, it wasn't until I took my first bite that I discovered that the white part of the bar was coconut milk. It might even be real coconut milk, as opposed to a fake coconut flavour. Trust me the difference is great and very important. Fake coconut flavour is often too sweet and generally horrible, where as coconut milk has a subtle coconut flavour and a wonderful creaminess to it. Even with the smooth coconut milk, I still wasn't sure about the black beans.
I've had red sweet beans many times in ice creams, candies and baked treats (particularly in Japan), but never black beans. Sweet red beans have a very distinct flavour that can work, if not too overpowering. Most of the time when I've eaten black beans it's been in a savoury context, and not sweet. As it turns out they're not too bad when used in a sweet treat either. They don't really add to much flavour in this case, likely because there weren't too many of them. What they did add is an occasional fun textured bite. The smooth coconut cream overpowered any bean flavour.
I can't say that this is for everyone, but for those feeling adventurous it's well worth a try. You probably won't be grossed out, but you may be wondering why it works when it probably shouldn't.