Put the summary of the bug you're having here
What I expected to happen was...:
Get on my world with cutsom spawners
What actually happened was...:
The game crashed when my spawners loaded
Steps to Reproduce:*
1. make a spawner with custom NBT data in McEdit
2. Get on the world
3. The game will crash when the spawner is loaded
Environment
OS: Windows 8 (ver 6.2, arch amd64)
Java: 1.7.0_13 (by Oracle Corporation)
Launcher: 0.8.3 (Dev) (bootstrap 2)
Minecraft: 13w23a (updated Fri Jun 07 11:04:20 CDT 2013)
This crash only seems to happen when the mob has custom potion effects. I have some skeletons with custom armor and enchanted bows which don't cause the crash, but my Speed IV zombies do.