Easiest way to go endless without a nether creature.

5 paranormal slimes… Put calamity on one… a piece of hell on another. And topaz attunement on two of them(one in each row so you get first attacks to copy)… Put anything you want on the third(maybe resurrection code?)

One creature with blood dance and cloak and dagger… that way your creatures only take 1% damage and he’s invisible so he can’t be targeted.

Now smash your head on the keys until you win. 8)

Until you run into a refraction that 1shots 5 of your creatures and leaves the 6th at 1 hp, that’s a brilliant idea.
Or when you run into Eternal Rest, or a topaz+mortarman, or anything like that.

I’ve tried para slime setups and while they’re psuedo endless, there are way better ways to get there without them.

Ritualist.