I don't own Harry Potter, J. does. All I have is imagination.
Prologe
Forbidden Forest
They sat inside the car, waiting to smash into a tree and die because of that Aragog. When one of the Arcomanutlas jumps right in the windshield of the car, Harry used the cutting hex on the spiders, which left a long gash across its abdomen as it flew off. Harry turned to see the spider but it went away faster than he thought it would.
Forbidden Forest
When he was across the small pond and ready to cast his Patronus, he saw a small figure behind the trees, it looked like… a spider, or more accurate, an Acromantula. He did not wait and yelled "Expecto Patronum!" as Prongs leapt out of his wand and drove all of those dementors away. He turned to examine the spider more closely and saw the spider was leaving by climbing a tree when it positioned itself more diagonally, Harry saw a long gash across its' stomach. Just after he saw the gash, it went as fast as it came and faded into the darkness.