Energy Core

Energy Cores are power ups used during the Rival Battle with Shadow the Hedgehog in Final Rush on the console/PC version of Sonic Generations.

Description
Energy Cores appear as large, purple transparent orbs that float at extreme velocities through midair.

When playing the rival battle in Final Rush, both Sonic and Shadow race against each other to collect Energy Cores, which will flow down the course at high speeds. When a character manages to collect a Energy Core, another one will then appear further down the course.

Once either character collect a set amount of Energy Cores, (two on normal mode and three on hard mode) he will automatically execute a special attack at the opponent. In Shadow's case, he will launch a number of Chaos Spears into the course that can hurt Sonic upon contact, for then to launch one final Chaos Spear directly at Sonic. In Sonic case, however, he will perform an enhanced Sonic Boost that can direct floating meteors on the course at Shadow to hit him, for as long as he has energy in his Boost Gauge. As soon as the character's special move ends, they will have collect Energy Cores all over again to perform their special move once more.

For the player, the only way to win the rival battle against Shadow is to collect enough Energy Cores to execute Sonic's special attack, and then use this special attack to catch up with Shadow by hitting him with meteor debris and then reduce his Ring count to zero.