Snap Camera is a desktop application by the Snapchat folks which allows you to apply their filters (“Lenses” as they call it) onto your webcam footage. The cool part is the fact that the app also exposes itself as a webcam to your system. That way you can use the (fake) Snap Camera as the input source for Google Hangouts, Skype, Slack, Zoom, Twitch, etc.
To create your own Lenses, you can use Lens Studio. This YouTube video should have you covered.