The Lightning Rod passively redirects every Night Action to itself. This includes the Mafia's kill as well as all investigations, protections, and so forth.
In games with at least one protective role, this essentially makes the game Nightless until the Lightning Rod dies for whichever reason. Otherwise, this functionally makes the Lightning Rod the designated Night 1 Mafia kill while rendering all other power roles worthless during Night 1.
Lightning Rods are most often, but not necessarily, pro-Town. Perhaps also see Suicidal.
Lightning Rod may be X-Shot. If so, they may choose each Night whether to switch on the mass redirection. If there exists a scum Lightning Rod, it would be this variant.
Use and Power
It's unfortunate to be a compulsive Lightning Rod; however, it can certainly make the early stages of the game more predictable. Thus, it reduces swing. It is probably overall Negative Utility though.
The X-Shot version of Lightning Rod is not necessarily as bad, but only good for a last resort if it is known that it will not hurt other power roles (or if the Lightning Rod has a death wish...).
Overall it's mostly good for shenanigans rather than anything else; just watch for whether the game can be rendered Nightless.