Awesome new Dark troop (SPIDER)

Hey earlier i got an idea on a new dark troop and after a little more thinking as i came of how the diffrerent levels should be.

This troop is a spider who throwing out spider web every 8 second.
The spider web covers equal area as Healing spell and slows every defens attack speed in this area.

level 1 level 2 level 3 level 4
Damage per second: 15 22 30 38
Hitpoint: 450 600 750 900
Train cost: 175 240 305 370
Slow time: 2 sec 3 sec 4 sec 5 sec

Favorite target: Defens (x1,5 Xbows)
Damage type: Single target
Targets: Ground
Housing space: 12
Training time: 16 m
Movment speed: 24

What i mean with (x1,5 xbows) is that it slows down 37,5% instead of 25% on xbows!
It deals more Dps on xbows too.

I dont know yet how i want it to look. If u have an idea, you can write a comment. :)

Is the slow time of multiple spiders cumulative??