Gives a NullPointerException on the Goat NBT on joining a world after the bug is replicated.

Replication Steps:

1. Create a new world
2. Tame and name a goat
3. carry it
4. Crash
5. Rejoin world
6. Crash on world loading stage

latest.log

at tschipp.carryon.common.item.ItemEntity.getEntity(ItemEntity.java:188)
at tschipp.carryon.common.item.ItemEntity.func_77663_a(ItemEntity.java:140)

Might be related to Carry On.

It's related to Carry On, just managed to replicate the issue on my end.
But it only happens when you try to carry a MoCreature entity that's already turned into a pet.