After your edit, I’d suggest that the mouse was “uplifted” by the butter.

Since adding layers doesn’t happen very often, there is not really a ready phrase for it. Also we’re not sure how to add layers to the bottom of a pyramid. You could use “jacking up,” but that doesn’t imply making the base wider part?

Since adding layers doesn’t happen very often, there is not really a ready phrase for it. Also we’re not sure how to add layers to the bottom of a pyramid. You could use “jacking up,” but that doesn’t imply making the base wider part?