The laboratory is the most important building for your attack. You can spend Elixir to research/upgrade normal Troops and Spells, and spend Dark Elixir to research/upgrade Dark Elixir Troops. While the research cost is very expensive at a high level, it is always worth the cost because, after research, your Troops will be permanently upgraded to have better-hit points, better damage (training cost is increased as well). You cannot start any research when Laboratory is being upgraded.
What dark secrets do the Alchemists hide inside their Laboratory? Nobody has dared to look. All we know is that their research makes our spells and troops harder, better, faster and stronger! The Laboratory is the facility where you go to upgrade your Troops and Spells. For a single research fee of Elixir or Dark Elixir, a chosen unit’s health, damage and cost will increase by a small amount. The Laboratory takes up a 4×4 space. Different levels of Troops will receive graphical changes. If you upgrade the Laboratory while it is researching, the research pauses until the upgrade completes. You cannot cancel the research while it is in progress, but you can immediately complete the upgrade (usually for a rather substantial amount of Gems). Laboratories emit a purple glow from the entrances when upgrading troops or spells.
Laboratories undergo significant visual changes at levels 3, 6, 7 and 8.
- When initially constructed, the Laboratory consists of a tan octagonal structure with multiple door-less entrances. A mass of black tubing covers the center of the Laboratory’s roof.
- The level 2 Laboratory adds a large vat of Elixir mounted on one side, while the roof is reinforced with steel.
- At level 3, the Laboratory’s roof adds a large black dome with circular Elixir-colored ports.
- At level 4, the doorways receive gold trim, and a second Elixir vat appears on the opposite side of the Laboratory at level 5.
- The level 6 Laboratory receives a faceted crystal sphere on its roof supported by a black iron rod and a helical golden spring. Electricity periodically runs up the surface of the sphere.
- At level 7, the crystal sphere is replaced by a huge set of stacked circular gold rings, identical to those found atop the level 7 Hidden Tesla. The Elixir vat on the left side of the Laboratory is replaced with a larger one filled with Dark Elixir. The ringed structure on the roof crackles periodically with electricity.
- At level 8, the circular gold rings are replaced with a vertical tube glowing from the inside. The door posts turn to a dark red color. It seems that red fluid is filling the left chamber. The dial also starts moving back and forth rapidly, showing that the vat may be overflowing. During a troop upgrade, the vertical tube spews fire.
The Laboratory, along with Mortar, are currently the only two buildings that can only be upgraded once in every Town Hall level starting from Town Hall 3 to Town Hall 10.