How do you get the Batman filters on Snapchat?

What app is the Batman filter?

In what seems to be a growing response to Snapchat and their success with video filters, video call application Line has joined the foray by launching its own filter application, which includes a special appearance from the Dark Knight himself.

How do you search for a specific filter on Snapchat?

https://www.youtube.com/watch?v=q6jhh-tESPg