I Need HELP with a spell...

I noticed in some maps that a spell, instead of increasing the movement speed of allies, it decreases movement speed for enemies. I would be really happy ^_^ if u can tell me how to do that. I tried already. For example: i want to make a spell that does the opposite of Endurance Aura to enemies. I noticed you can only make it increase, not decrease .I'm stuck. Can u help? :god_help_us:

I might be wrong with this becuase I havent tryed it but you can allow negative values (in gameplay constants I think) after you do this you can get endurance aura to reduce speed.

It is on the editor preferences, "Allow negative real values".

For anyone seeking the same help, not finding this, it's under File -> Preferences

I would like to thank you for your help. Now I can finally finsh my map. Once again, thanks.