1. Summary: This battle is just a test of dodging and waiting. The BOSS has a different set of attacks, and you need to dodge all of them, and eventually the BOSS will explicitly start making stabbing moves with her tentacles. At that moment you need to stand in front of an electrical box and then dodge at the last moment to let her stab it and electrocute herself.
2. Specific operations
1. A sweeping signal is sent out when one of the tentacles bends to one side. Once it starts swooping, just jump up and pay close attention, and it may immediately signal again that it thinks it's coming from the other side. The BOSS stretched out a tentacle upwards and launched an overhead attack. Get aside.
2. Then there is an attack. The BOSS extends a tentacle into the ground and shoots upward from below while it tracks you. You'll need to dodge to the side here too, but you're free to do whatever you feel like early on without being punished like an overhead attack. The floor can be completely electrocuted, and when that happens you'll need to keep fighting until it won't let you anymore.
3. There was also a place where only a quarter of the floor was electrocuted at a time. Stay near the point where the 2 quarters meet, and when you know which one is going to be hit, you just grab the other while focusing on your normal attacks.
4. Finally, there is a section where the electrocuted ground begins to rotate. Here, you should try to stay in the middle of the ground without electricity, giving you some wiggle room to dodge normal attacks.
The above is all about how to fight Mara the Ghost Walker. I hope it can help everyone.