The Spider-Banishing Charm
Arania Exumai was a charm used to banish or blast away spiders and Acromantula. There are limitations on what the spell could do, particularly amongst large numbers of Acromantula, creatures that are markedly more intelligent and much bigger than standard spiders. In the Chamber of Secrets film, Harry witnesses Tom Riddle use the spell against Aragog, and so uses it himself when one of Aragog's many family members attacks Ron.
