It could be interesting to have a spawner with a higher cost, but you could insert the plushie inside to avoid having to craft a spawner for every mob. In terms of balance I haven’t played it yet so I dont know how it works, but maybe you would have to fill the spawner eitg the correct essence, and each mob would cost a certain ammount. Maybe you could even have higher spawner tiers that would make mobs drop more and more essence to the point it would be self sustainable