As it currently stands, eel hat mostly serves as a padding tag for Otomachi Una. Of the 604 posts currently tagged, only 4 don’t feature her (one of which actually includes Una's hat). Given this, I don't think the tag is particularly useful for searching. I think we could either add posts of other characters that wear an eel hat (if there are any), giving it utility beyond just being a tandem tag for Una, or alias it to a broader animal-themed headwear sort of tag, if we can't find other characters with eel hats.