I guess Supergirl won't be walking through any haunted houses tonight if a spider makes her this terrified.
Nor do I think I she'll be handing out the candy tonight if a Cowboy costume scares her this much!
"The Frightened Supergirl" was the main story in Adventure Comics #401. Written and drawn by Mike Sekowsky, the story involved Nasty Luthor slipping a fear potion into Supergirl's water making the Kara run amok from fear.
In the end, the whole story turns out to be a dream.