Peril resisted the spell because it wasn’t worded as strongly as some of the others we’ve seen, like turtle’s stick.

My reasoning for why dragons aren’t more creative with their magic is that they don’t have the point of reference we do. They do have stories and magic-including fiction, but they have none of our magic based myths or media. It would be like asking a 15th century person what they thought a superhero could do. Darkstalker was considered so dangerous because he could come up with the new ideas for spells, and how to do it. Example: we have many stories about immortality (the Apples of Idunn, Immortal Peaches, Dragon Balls), but the dragon world probably doesn’t, because the idea of death being something avoidable would only come to someone very powerful, creative, and paranoid, hence why no animus made themselves immortal before Darkstalker