School on its head, or the day everything went wrong

Since the morning, Staś had a strange feeling that this day was going to be completely different from all the others. When he entered the school, he immediately noticed that the clock was hanging.... upside down. "I think the maintenance man made a mistake," he muttered under his breath, but no one but him paid any attention to it. In the corridor he met his best friend Susie, who looked amused. "Staś, did you see Mrs. Janitor singing to the mops today? And operatic too!" whispered the girl, trying to hold back a giggle. Staś looked at her with wide eyes. "That's nothing yet! I saw the nature master talking to the fern and apologising to it for the broken leaf!" In the maths room, the children found the class hamster, Professor Gryzol, who.... was sitting on his desk, wearing the teacher's hat on his head and chewing away at his notebook with something resembling multiplication tables tasks. On the wall someone had stuck a huge piece of paper: "Stranger Things Day!" When the children tried to sit down for a lesson, it turned out that the chairs were on tables and instead of textbooks they all had.... cookbooks with recipes for laughter soup and wrapped pancakes. Then the bell rang, but instead of the usual sound there was the crowing of a rooster! The children looked at each other in disbelief. Suddenly, a quiet giggle sounded from behind the door. Through the ajar crack, the tail of a .... of a purple cat, which in one paw held a large board with the words: "Here we go! Who can guess what will happen at school today?"