Defaced ink pad

I've been doing a bit of crafting this week. Just recently I bought an embossing heat tool and I'm loving it! I've been making some gift tags to go on treat bags for the girls' teachers for Valentines, and of course Valentine cards. So anyway, Morgan and I were getting our craft on the other day and I noticed this little addition to the girls' ink pad:

Hmmmm, I wonder who did that?