Eldritch monsters they are never gonna fucking reach

I would create Eldrtich Monsters, as mentioned by @Scarlet king999 but also I would take inspiration from mythological monsters like Medusa, Kitsune, Asura, etc. for they are powerful and it is going it to be a hard/impossible fight for them to ever reach me.

A monster that requires being hit 1000 times to be damaged then cover it in a slime that takes 100 unique attacks to kill so if it’s hit with a sword it can’t be damaged by a sword for the rest of 99 hits but when it dies it’s ability transfers to the monster it was attached too meaning it requires 1100 unique attacks to even start damaging the real boss

Easy

I create very sophisticated slime.

Durable,very adaptive, cute.

Almost universal being.

I can add simple replication power to slime and allow it become metamorphic being that have abilities of hundreds of beasts.

If talking about core of slime . I can create not one but ten little core that exist in other parts of body and with magic any core can replicate whole slime if previous destroyed.

It may be t-1000 terminator that originated from slime beings.

I will create monsters based on mythologies and stuff e.g.

Fenrir

Quetzalcoatl

Bahamut

Jack o Lantern

Ogre

Arachne

And many many other bosses and monsters

I create a mountain sized fire breathing dragon called Armageddon who is constantly surrounded by smaller dragons the size of houses