Just as the title says, I can move a captive biter spawner. Considering that you can't normally pick them up, I'd consider this a bug.

(that being said, I'm laughing like crazy as I drag this single captive biter spawner from all the way across the world cause I pushed the biters like crazy and then put down some artillery, so this is going to be a like, 20 minute journey, and I'm sure to be cackling the whole way cause of how stupid this is. So, while I'm considering this a bug, I am also absolutely going to abuse it for now. Being able to hold a direction key to just get it to fly in a direction would also be nice, but uhh, usually you don't use picker dollies to move entities across the world but only by a few tiles, so it makes a lot of sense why that's not a thing..)

Edit: it only took me around 10 minutes, so 20 was an over exaggeration. Still laughing about it though!

:-)

Do you have teleport mode activated by any chance? Or enabled cheat mode in the mod settings?

I will add this to the blacklist; In all honesty I almost always play with enemies disabled because I enjoy the building aspect of the game but not the fighting part.

https://github.com/hgschmie/factorio-even-pickier-dollies/issues/8

No teleport or cheat mode as far as I know! I'm playing with Enable All Planets Lite ( https://mods.factorio.com/mod/kry-planet-mods-lite ) (though without Castra ), and some other QOL stuff that I enjoy (copy-paste modules, Helmod, rate calculator, ghost counter, orphan finder, etc).
Playing in a default settings world beyond all the mods.

Honestly fully fair about playing on peaceful mode. I enjoy the enemies cause of the pressure they bring - they give me a reason to struggle in the early game. Late game/once I get into megabase territory I consider turning them off cause they become more enemies of UPS than enemies to the factory though.

A captive-biter-spawner is actually not a unit or a unit-spawner but an assembly-machine. And as those can be moved, the captive-biter-spawner can be moved, too.

Fixed in 2.7.0.