User blog comment:Darkcloud1111/''The Mark of Athena'' Plot Holes/@comment-31427049-20170302021121

This isn't a plot whole either, but i would like to point out that at the beginning of the first series, Grover uses a three fingered claw on Mrs. Dodds, and Percy uses it on Gabe. When he does, the door closes on Gabe, implying that it has some special power. This symbol never shows up again