Rare Light Tower - Crystal Monolith

Name: Crystal Monolith Cost: 1500 to 3000 Attack: Fal Range: 3 Cooldown: 4 s Element: Light Gender: None Damage: 10-20 Crystal Focus: When no creeps are in range, it sends its light to the highest level Crystal Monolith contributing 20% of its base damage. I'm not sure what combination of tower base damage and contribution % would be balanced. I imagine this working like a wolf build, but requiring more investment. I like that this fits the light style: guards helping each other, hologram gaining levels, then Crystal Monolith to capitalize on those leveled towers. Maybe instead of 20%, then perhaps 15% (+0.1%/level), but that makes the bonus scale quadratically and be extra weak at lower levels. Or the base damage of the tower could be reduced and the contribution percent increased. Maybe base damage = 5, and contribution is 40-60%. It would be a garbage tower without friends and would need gargoyle to stop creeps from reaching the supporting Monoliths. --- This is just an example of the other extreme. Somewhere between these two amounts should be a fun, balanced tower. Edit: Added cost. I feel like a higher base damage tower (which is less reliant on its fellows) should have a higher cost, while a lower base damage tower than is useless without its friends should have a lower cost.