New dark elixer troop

Goblin engineer (similar look as goblin but instead of bag he has a wrench or tool box.)
Ability-take over enemy defences and use those to destroy other defences. Your units will not attack this defence until the end
Hp- low to medium hp
Dps- melee low
Speed- same as goblin
Training cost- medium
Training time- about 10 mins
Unit space- 5

This would make it so that people don't leave their defences that they can't fit inside their base on the outside. Say a goblin engineer gets into your xbow then your xbow will turn on your base and attack the structures.

I anyone has ideas similar or a different statistic value reply and let me know what you think of my idea.