Pikachu strikes a series of synchronized poses with its Trainer to build Z-Power. It then leaps into the air and absorbs electricity from dark storm-clouds that have formed above it. Pikachu then fires seven bolts of electricity, each a different color of a rainbow, at the opponent.
This is the only move whose English name starts with a non-alphabetic character.
This is also the only move to naturally have a sharply increased critical hit ratio.
The name of this move is partly based off of the Japanese name for Thunderbolt, 100,000 Volts. The 10,000,000 figure references that it is an upgrade of Thunderbolt.
Along with Catastropika, 10,000,000 Volt Thunderbolt is the only species-exclusive Z-Move to have a unique pose not shared with other Z-Moves of the same type. Coincidentally, both are exclusive to Pikachu.