>>41007751
>>41007786

I was gonna say this: >>41007781
That's 100% some kind of animal. It's difficult to make out, but at the 0:06 you can see how when it turns its' entire body to change direction it actually starts with its head and quickly snaps the rest of its' body behind it before darting off. It also moves like an animal: organic, flowing, clean, movements, capable of intense spontaneous bursts of speed with little air-resistance or disturbance.
You can also see it a little more clearly in the slow down: >>41008292 there seems to be some sort of translucent frills or fins underneath the body like how a marine animal would. It seems to unfold them to cushion or control it's descent near the water - doing a playful little dip before it hugs them against its' body and zips around.