How would I go about...

[Jayronathon]

getting a webpage to have the Bat effect that happens in the videogame. an example of the effect would be say fo instance, when you knock out the last guy on a screen and the bats fly across the screen.

How would I get just that animation from the game and convert it to like maybe an animated gif?

[Smashman]

I don't think it's possible.
It's probably a particle effect, and not a gif or anything...

Although the menu screen one could be..
Ask a modder to look into it.