Mod Version:
DynamicSurroundings-1.12.2-3.6.2.1

Forge Version:

Link to client log:
Pastebin won't let me put the log file in it.
latest.log

Link to crash log:
No crash.

Description:
Title.

• Did you just add the mod to a pack?
  Yes. This is due to the Aether mod. Tried with just these 2 mods.

• Did it just start crashing, or has it always crashed?
  Read "Link to crash log:".

• Did you update any other mods in your pack and it started crashing? This includes Forge.
  No. Read below.

• If updating multiple mods did you update one by one or all at once? To help narrow the problem down adding one by one is helpful.
  Everything's on the latest version. I would give a list but I'd rather not make this issue 99999 pages long.

• Is the modpack you are using available online somewhere? If the crash is due to mod interaction having the pack available makes things much easier. It is much harder to work these types of issues with a private kitchen sink pack containing 250 mods.
  At the moment, no. Read above.