Something Big
This is part of an advertising hoarding for a ānew smart app for you and your smart petsā. Iāve no idea what it was for but the original poster showed a white mouse. Mustāve been inspired by Hitch Hikers Guide to the Galaxy HG2G.
It would appear from my Google searches for the actual product being sold that āsomething big has arrivedā is a very popular advertising slogan. Iām sure you can find many more reasons to use this phrase: sizeable babies, surprise birthday cakes, sonic booms.