It is his weakness; he has to stay away from it or it kills him. It’s his silver bullet for a werewolf; his garlic for a vampire; his sin for a human. It is his predator. It hunts him out every day. It is kryptonite; he is Superman. When he is near it, to causes him to regress and not be so super.
It’s a super installment for Flash in the Pan. The word was regress; max word count was 75 words. This comes falling out of the sky with a total of 63 words. To read other super additions to Flash in the Pan, follow the link.