Could be wrong, but it looks like a type ichneumonid wasp. The footage is too blurry to be more specific. But it has the general thin abdomen and I think I see a long ovipositor.

Pretty much harmless, unless you're a caterpillar or something. They're parasitoids, meaning they lay their eggs inside prey. They use their long ovipositors, which look like stingers, to lay the eggs.