This trap looks like a button and whenever a troop steps on it, the nearest defensive building around will do double-damage for a certain amount of seconds. After the double-power is done, the trap is broken and must be re-armed in order to use again.

Unlock at TH 8.

Level 1: 5 Seconds
Level 2: 6 Seconds
Level 3: 7 Seconds
Level 4: 8 Seconds

Level 1 Cost: 30k (TH 8) (3 hours)
Level 2 Cost: 150k (TH 9) (12 hours)
Level 3 Cost: 300k (TH 10)(16 hours)
Level 4 Cost: 500k (1H 10)(1 Day)