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Kernigh
Since: Sep, 2012
2013-09-10 18:03:14
That sounds like a flavor of Mirror Boss that requires an Outside-the-Box Tactic to defeat. It might also count as a Puzzle Boss.
BinaryStep
Since: Dec, 2012
BinaryStep
Since: Dec, 2012
DAN004
Since: Aug, 2010

Is there a trope for a boss fight where everything you do is flipped (like if you attack the boss, you hurt yourself, or if you use a health potion, the boss regains HP)? Typically, the boss is destroyed if you hurt yourself, which makes the boss hurt itself.
Cain from SCP Foundation is kind of an example.