Biting off several mouthfuls
This is one of those projects that seemed quite straightforward to begin with; the idea was that over six panels, two characters would have a conversation - displayed as picture bubbles rather than speech - with the pictures growing more elaborate as the conversation went on. It wasn't until I'd drawn the characters (very simple, cartoony figures) that it became clear that this story was going to take a lot more work to illustrate than I'd anticipated. The pictures in the "speech" bubbles had to be done using a combination of photos, painted and 3D elements, and required a steep learning curve to pull off. (On the plus side, I now know how to paint lightning in stormy skies - thank you Clip Studio.)
Of course, I could have just drawn the pictures in the dialogue balloons, but (imho) the visual gag wouldn't have worked anywhere near as well.