Lightning Stake is a very potent offensive miracle to use, but it is designed for use at point-blank range, as the name of the miracle implies. It does heavy lightning damage to anything struck by the immediate impact of the bolt, as well as sundering their poise.
Interestingly enough, an enemy can be struck "twice" by this miracle, as the bolt itself seems to do damage (although low) prior to being thrust into the ground.
The large impact radius also allows it to hit other enemies in the immediate vicinity as well to the same effect, though targets caught in the dead-center will take notably more damage.
It is highly advised to cast this miracle with a talisman that has the "Unfaltering Prayer" skill, which will allow the caster to channel this miracle with little worry about being staggered when in combat.
The animation when casting Lightning Stake is very similar to that of Lightning Spear, prior to it being slammed into the ground, which in terms of PvP, can be used to deceive players and have them roll towards the caster to evade it, but instead get struck by the stake itself.