@MizKai All vanilla randomly spawning iron spiders are equipped with a special backpack (a transparent one that they don't actually carry on their back). Weapons are always included and their performance is random.
However, I believe the iron spider in the spider factory contained loot from the ruins, not a weapon.

also does the backpack spawns on spiders with rates chances? or all the spider around ur world spawns with backpacks or only the weapons has a percentage to spawn inside the backpacks

Got Question. how did u add backpacks on the spiders?

@poly Yes. I searched percentage it using FCS

You can find at 1% . Edge variant is 3%

is there a meitou variant?

Thought the backpack would enable a third arm for Skeletons lol

@buster he made that a mod too lol

this thing is wayy to op, one with unreal manufacturer does over 5.50 blunt damage. this thing literally weighs 110 kg holy shit

Thanks. The description makes it sound like you could use it to attach the spider arm to a skeleton player - which would be some really neat functionality, but probably impossible. Thanks for clearing that up.

@Buster It's just a container. I couldn't put weapons in Iron Spider's inventory, so I had to add a backpack. Skeletons can be used as backpacks for very small inventories with no demerit. There is no point in putting a spider arm in that backpack.

I'm a bit confused by the "Arms Joint" backpack? Is it just a container for the weapon or does it have functionality? Am I suppose to keep the spider arm in the backpack and attach it to a skeleton?

any chace of making tem aplicable to the cannon mod?