Harry sure had had one crazy week, first luna was being burned at the stake and all of that about the pot snatching "poterghast", and now here he is alongside Blue the apparant Stegasaurus who was all jumbled up after getting caught in a stampede, Blue got seperated from the rest of the velociarptros and then ran smack into a stegasaurus so hard that vthey switched bodies.
when harry hears Blue's plight he immedaitely agree the hlep. blue takes all fo the hlep harry has to give but is still stuck inside of the stegasaur body, that's why Blue becomes very sad. "Well I guess I'm stuck as this now," Blue decided, that's when Harry got an idea. "But wait, what if I build two giant slingshots out of these tall redwoods growing so abundandlty in this grove here," they were standign inside a giant prehistoric redwood grove)," and then strap you into one of them and go and find the stegasaurus who is stuck in your velociratpor body and strap her into the other one and then slignshot you into each of your own bodies!"
Blue agreed that was a great idea and went with harry to the store to buy chainsaws to cut down all the redwood trees. Harry figured he needed at least 20 of the ancient trees, but figured it would be safe to go ahead and just cut htem all down in case some of them are better than the others and would make a finer material for the slingshots, which would only be apparant once the wood had been logged and processed. this all took about a year, that's when Snape made his move!