by looking at this video, it seems this was done with some of a cartoon FX pack (google it) and was created in a traditional animation software like Animate or even photoshop. judging by the animation it only looks like 5 frames or so in loop. so just create 5 of those frames and you are good. you can create something like that with After Effects shapes.
create a triangle path with a fill

add a repeater. set the anchor point and rotation

add wiggle transform, change it's postion and add wiggles/sec

duplicate the layer and change the triangle to something a little different

here's the project for you to experiment with. press UU on the layers to see all the modified properties.
Spark.aep - Google Drive