The Slime Spell

Slime Spell:

This unique spell targets pesky defenses that would otherwise ruin your attack!
When dropped on a defense, the slime brewed in the spell makes the defense slower to attack.
The spell would slow the defense down by a specific percentage and that percentage would go up
after upgrading.
I think this spell would make a fantastic addition to newly revealed Dark Spell Factory and would
allow air raids to get some of their effectiveness back after sliming those pesky air sweepers!

Please reply and leave your thoughts on the spell idea!

This is a worse version of a freeze spell