After Minerva had left him, Horace was about to run to the school grounds where the enemy forces had congregated before he hurried back to his quarters. Earlier in the month, he was teaching one of his classes how to make a strengthening solution and had made an improved one of his own. He charmed a protective bubble around the cauldron and started levitating it through the castle, jogging after it in the hallways. He looked through the windows that he passed and saw an army of giants gathered outside the shield, making him even more sure of himself. He rushed all the way to Hagrid's hut where he found Hagrid and Grawp along with Fang. Horace had only found out about Grawp after he and Hagrid had went out to the Three Broomsticks again. He wheezed his way over to Hagrid's hut and told Hagrid of his plan.
"I have made an improved strengthening solution and the entire cauldron worth should be the right dose for Grawp. Given how small Grawp is compared to the other giants, and how many other giants there are, Grawp won't stand a chance."
Hagrid looked like he would resist having this potion administered on his half brother before he nodded along, "Drink up Grawpy," the half-giant shouted. Horace removed the enchanted bubble from around it and Grawp picked up the cauldron, lifting it above his mouth and then turning he cauldron over, drinking all the strengthening solution. Seeing this, Horace nodded, took the cauldron and ran back to the castle, wondering if it would be enough for Grawp to survive the other giants.