Comments posted to our Dark Souls 3 Wiki
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Does not *****ing work on dagger and greataxe snakemen. Invisible the whole time, chased and attacked me from the 2nd bonfire (after wyvern) to the great belfry. *****ing horse*****.
This makes thematic sense. Snakes have very poor sight, but amazing sense of taste, which translates to smell for them. Aka, they don't see you to begin with, so going invisible means nothing.

Devil's Advocate aside, this is FromSoft. They can't even program GS or UGSs to be moderately balanced, you think they'll spend time on making the game FUN?