I started recreating my oldest uploaded model on a whim and posted a picture in the media. I got feedback from @Footman16 and @deepstrasz, and the work evolved from there. I am considering creating destructible doodad variants, but only if that would potentially be helpful to anyone. The spawner is a hybrid unit/structure similar to Robo Factory. It works best pre-placed in an RPG or tower defense mod or as a waygate/teleporter. I did create a simple Birth animation, though.
There is a little trick if you want the spawner to train units without it being a structure in a fixed position.
1. Base the unit of Robo Factory. It has the Rally ability and stuff. (I learned that rally comes with being able to train regardless.)
2. Tick "is a Building" and click on another unit.
3. Return to the spawner, and the option to train units is now available. Add whatever unit you want it to be able to train.
4. Untick "is a Building," and the spawner can train units in-game now. The only problem is you will not see the training time bar.
-Update. Cave version
-Update. Cave version without spider stuff.