Hey Prakash, I talked a bit about this effect, “the boil,” but probably could have elaborated! The boil is made by drawing the same frame multiple times. For split second moments you can just draw them manually in a series for however many frames it takes, say, 6. One of the reasons I switched to Rough Animator is that it has a “cycle” feature that I think I also mentioned, which let me boil over a longer time period. I would just draw 3 frames and cycle across, say, an additional 21 frames for a 2 second boil. It’s important to draw the frames with as little deviation from each other as possible, or the boil will look too jumpy. Hope that helps!