Statues are blocks that serves to obtain PE (Potential Energy) when right-clicking with a Necronomicon.
Each statue represents one of the "Great Old Ones" from Cthulhu Mythos. There is also a decorative version of these blocks that don't have any uses in particular.
You can find them in structures of Darklands biome, above a Monolith Stone Pillar.
Statues supply PE to any valid energy acceptor only within a certain range of itself, which can be seen by occasional particle effects going between the statue and the energy acceptor. They do not need line-of-sight, as the particle effects will happily go through any blocks in the way and PE will still be gained.
The base range of a statue's PE transfer is 3 blocks horizontally and 0 blocks vertically (ie. they will transfer to anything within a 7x1x7 volume centered on the statue).
Placing a monolith stone pillar underneath the statue will increase the range by one in all directions except upward. That is, statues will never transfer PE to an acceptor which is higher up; statues must be placed above the acceptors in order to transfer. Placing a second pillar underneath the first will also increase the range another block, but any further pillars beyond two will have no effect.
Applying a charm with a range amplifier will increase the horizontal range by another 2 blocks in any direction, 3 if the amplifier's deity matches the statue, but has no effect on the vertical range. With the proper charm and two monolith stone pillars underneath, a statue can transfer PE up to a distance of 8 blocks away horizontally and 2 blocks downward.
Statues will only be effective up to a maximum of 20; any additional statues in range will not transfer more PE.