Modifying Creep Mechanics

[Patcharoo]

Where in the world would I find creep to modify it? Just in effects?

I have recently played a mod called Heptacraft in which ground mechanical units become slowed on creep. I was hoping to recreate a similar outcome, but while searching through the mod I haven't had any luck figuring out how it was done.

 

[Dr Super Good]

Modify the unit's "Creep Speed Multiplier" and "Creep Speed Bonus fields". A Creep Speed Multiplier value of 0.6 will mean a unit will be slowed 40% (move at 60% of original) when on creep.

For other more complex effects on creep you can use a behaviour with a creep validator to turn it on. This is probably how Zagara's armor talent works in Heroes of the Storm.