We also having a toddler so we buy lots of toys (that have to have lots of disclaimers and warnings in many languages to reduce liability).
The word that I have seen that is the same in the greatest number of languages is "slime". It was basically the same in the greater than 30 or so languages I saw it translated into.
I think it is a word that no one wants to claim and make theirs, I suppose.
I was going to say it is a new word and that that is the reason it is the same in many languages, which I think is probably true - but it shouldn't be. Because after all slime grows on many things that are decomposing.