What is the logic to kill this phantom?

Sometimes when I attack this enemy, it simply changes formation.

Sometimes it does lose life, and end up killed.

However, I couldn't figure the logic out.

Solution 1:

Every ghost comes in a pair, where only one half can be damaged at a time, with the entire ghost dying when one of the halves is destroyed. The half that can be damaged changes when you hit them, regardless of damage dealt.

So, the way to deal with them is:

• Hit whichever half with a weak attack, but take note of which half you hit. For example's sake lets say you hit the left one

• If it dealt damage, you know the next time you'll need to hit the right half and can now hit full force

• If it didn't deal damage, hit the same half again on the next turn. That's because the half that can be damaged changed with the previous hit, even if it didn't deal any damage