I know of the burrowing system, and I'm trying to implement it into a map. The only problem is I can't create a damn burrowed unit. I tried the 'Create Unit with Special Properties' in SCMDraft, except it just creates the zerg unit without any special properties... What am I doing wrong? I just want to create a burrowed zerg unit!

The player owning the unit has to have burrowing researched by default.

Two things could've gone wrong:

1. Burrowing is not researched for the player you're creating the burowed units for

2. If you're using over 64 sets of properties in the 'create units with properties' action, it won't work.

EDIT: Just so you know, you can achieve the slowing effect by creating air units above your unit also.