Continued work on Witchworks (minecraft mod) has now arrived at "Okay, I now have a bag you can catch monsters with, turning them into eggs, and then put in an incubator to generate drops".
Which in turn makes "I want to brew regeneration potions, so Ghasts" and similar from lots of hunting to a one-time quest and then some labwork.
Which means I want to swap out the current summoned critters for novel ones, so summoning doesn't short-circuit that hunting.