An unknown device has appeared on AnTuTu, supposedly sporting the Qualcomm Snapdragon 660 processor, and it scored 105,576. That's a pretty high score for a mid-range chipset. Now keep in mind that the only proof that is available that this is a Snapdragon 660 device is the name that AnTuTu shows for it. Which is "myDevice sdm660 for arm64", so it's not confirmed that this is indeed a Snapdragon 660-powered device, but it is fairly likely. With this score, it's sitting at number 25, below the Meizu Pro 6 Plus which sports the Samsung Exynos 8890 octa-core processor along with 4GB of RAM. So that shows just how good this benchmark score really is.
Now it's important to note here that the Snapdragon 660 has not been announced yet. It had leaked several times over the past few months, so we have a good idea of what to expect from it. According to leaks, the Snapdragon 660 is a big.LITTLE octa-core chipset, featuring four 2.2GHz cores and four 1.9GHz cores, and it'll be manufactured on Samsung's 14nm process. It's supposedly being paired with the Adreno 512 GPU for graphics as well. Of course, take all of this with a grain of salt, as none of it is actually confirmed until Qualcomm makes the processor official.
The Snapdragon 660 seems likely to become the latest high-end of the mid-range set of processors that Qualcomm has available. The Snapdragon 600-series is always a step above the Snapdragon 400 which is seen in a lot of mid-range devices, but not quite where the Snapdragon 800-series is, like the Snapdragon 835, which is set to debut in the Galaxy S8 later this month. The Snapdragon 660 appears to be an updated Snapdragon 625, which wasn't seen in a whole lot of devices in 2016, but in the few it was seen in, it provided great performance as well as great battery life.
It's also worth pointing out that this is likely not a smartphone from a manufacturer. It is very likely that this is a reference device that Qualcomm built to test and run the Snapdragon 660, to see just how good it runs, and if it needs any fine tuning. This is a very common practice for chipset makers like Qualcomm. MediaTek, and others do it as well.