Mod Version: 3.6.1.0
Forge Version: 1.12.2 14.23.5.2854
**Link to crash log:
crash-2020-11-22_22-11.txt
**

Description:
Yesterday I installed forge 1.12.2 (client + server) + 35mods
was fine for a couple of hours, 1 client had game crashes
today next 2 clients have crashes, including me; same crash report (as in file)

I tried to update to ver. 3.6.2.1, 3.6.2.0 - unable: server doesn't start, frozen at line: "[CSRV] Executing Java..."
when i delete mod (in newest ver.), server goes on, no issues

maybe conflict with 'animania' mod because short crash message shown by Minecraft says:
"The game crashed whilst rendering entity in world
Error: java.lang.NoClassDefFoundError: com/animania/common/entities/sheep/EntityEweBase
Ending code: -1"

Tschipp posted an update for Animania that should address this issue.

See #573. Make sure you install the other Animania mods because of cross dependency.

What i've done:
I tried do downgrade DS to ver. 3.6.0.2 - no changes
I uninstalled DS - no changes (!) so it doesn't look like these 2 mods dependencies (at least this issue)
I uninstalled animania-extra mod (animania-base and animania-farm left installed) - it's OK!

So i lost a few animals (including beautiful peacock), but I still have most of them and have DS, so I don't have to resign any of them :)

ps. still don't know why sheep according error (com/animania/common/entities/sheep/EntityEweBase) appeared while crash..?

Cross dependency. In the 2.0 version of Animania the mod was essentially split into 3 separate mods. Turns out that one of those mods has a dependency on code in another, and if that mod is missing you will get this exception.