Yes, the OP knew that they uploaded a picture of a wrench. That banana is there just for scale, in case you had no idea how large the wrench actually was. Anyway, the OP wanted to know whether this was a novelty item from a joke shop or whether it served a real purpose.
Regardless of how hilariously humungous this wrench is, it actually serves a real purpose. Towers are put together with big nuts and bolts, and only a big wrench can fasten them securely. Which begs the question, why don’t they make big pneumatic impact wrenches? That’d make life easier, wouldn’t it?