First of all: very good work - best spiders so far and I love it.
I have an issue caused by your mod in combination with my favorite shader: SEUS

Versions:
Minecraft 1.12.2
SEUS-Renewed-v1.0.1
spiders-2.0-1.12.2-1.0.2

I made some screenshots with Mo' Bends and without.
I have to turn off the shader to get rid of the problem.
I haven't found a configuration of the shader itself to get rid of it.

Sorry if I forgot something, it's my first post on GitHub.
Keep up the good work.

Screenshots:
Without Mo' Bends // with SEUS shader:

With Mo' Bends // with SEUS shader:

With Mo' Bends // without SEUS shader:

With Vanilla-Spider everything works fine:

Thanks!
Could you please also report this to SEUS? The better spiders renderer doesn't really do anything unusual that I know would break shaders (it simply rotates the regular spider model).
I'll do some testing though when time permits.

Thanks for the quick response.
I purchased the new SEUS PTGI shader yesterday and have done some testing.
I also tried Sildurs Shaders 1.24 and with both other shaders the texture of your spiders works correctly.

It seems to be an issue with the SEUS Renewed shader only, but still it's a very strange issue. I first thought it is some kind of a light reflection problem, but even if I eleminate all light sources, the spiders still "glowing". If I find a workaround somehow, I will let you know. For now the only way I see is to use another shader, because it's very gamebreaking.

PS:
I haven't found a way to contact Sonic Ether, but on his Patreon side he clarified that he is working on the new PTGI shader and barley will make upgrades or trivial fixes for older versions.

Edit 09-10-20:
I tried other animal mods. In Better Animals Plus some textures have the exact same issue - so it's a SEUS Renewed problem and not your fault. Best regards.

At last:
itsmeow/betteranimalsplus#65

This is the exact same issue in betteranimalsplus - I tested it.

Interesting, because the glow layer is an exact copy of the vanilla spider's.

Hey again,
I have done some playing and testing this week in my modpack.
I figured out why the spiders are glowing and I thought you want to know.

It has to do with "emissive textures" from Optifine in combination with the SEUS Renewed shader.
It's definitely not your mods problem. It's because you use emissive lights somewhere on your spiders texture, maybe to make the eyes glowing in the night or something like that. That's an upgrade and a good thing.

The shader now has a problem rendering it. For me the SEUS, but maybe on other shaders too. I hadn't time to test all of them. For example: The same effect is on the "owl" in "Exotic Birds" or on the "wolves" from "BetterAnimalsPlus". Both use glowing eyes in the night (emissive textures) and for some reason the shader can't handle/catch it and instead make the whole entity glowing.

Maybe you haven't done anything about it and just used the old vanilla textures. However, it just occurs on modded entitys. As soon as it is modded and has emissive textures (something with glow effect - emissive lights).

The only thing you could do, would be removing the emissive textures from your spider. I think that would be a downgrade and not worth it - but I leave it to you. I just want to write it down, if someone else has a similar problem. Maybe you can add to the issue title "glowing textures / Optifine / SEUS" or write an "incompatiblity for SEUS Renewed" in your mod description. The nearest solution is waiting for the SEUS PTGI shader release or use another shader.

If you want to reproduce just download the latest Optifine and SEUS Renewed Shader from their websites and use them with Spiders2.0 or any other modded entity with glowing eyes. The problem occurs immediately.

Best regards and keep up the good work!

Hey, thanks for looking into it! I did expect it'd have to do with emissive textures/lightmap. Maybe I can figure out how to make it compatible.