These are made using an idea from Rod over in the Compiled APNG plug-in thread. He said that he had used Jolie's Hulkify tutorial to make an elephant he posted in the APNG thread.
The whale is a dingbat and I made it, alpha to selection, then Selection to Path and unselected it. Then I made the small gray rectangle. I moved it so that it was completely covered by the whale. Moved it to the top layer and duplicated it. Then Select > From Path so that I had the elephant selection.
Followed this tutorial except I completely filled the rectangle in the iWarp window with gray. Then made the animation.
The present and Party Text was done the same way. The present was duplicated. Then I did Select > From Path for the text. To the iWarp filter. Then filled in the whole iWarp preview window with the red and yellow from the package. Made it into an animation. As you can see, since the package was not completely hidden by the text it shows under the text. The original, red text layer was moved to the top, Select to Path, Select, Shrink 2 and deleted. Then the hollow text was merged down to the top layer of the animation.
They are both gif files.