This is part of an advertising hoarding for a ā€˜new smart app for you and your smart pets’. I’ve no idea what it was for but the original poster showed a white mouse. Must’ve been inspired by Hitch Hikers Guide to the Galaxy HG2G.

It would appear from my Google searches for the actual product being sold that ā€˜something big has arrived’ is a very popular advertising slogan. I’m sure you can find many more reasons to use this phrase: sizeable babies, surprise birthday cakes, sonic booms.