A kaboomery can be placed by using a build allay, which will cost 250 wood and 150 coal.
Usage
When placed, the kaboomery creates a zone around itself. Any arrow towers, scatter towers, or redstone launchers in this zone are given an explosive shot which increases their damage. If the kaboomery is destroyed, all affected structures lose their explosive shot.
Quotes
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Adds an explosive damage to projectiles shot from the arrow tower, scatter tower and redstone launcher. Requires coal in order to build. For a structure to be affected, it must be inside the zone the kaboomery creates. If the kaboomery is destroyed, affected structures lose their explosive shot.