Jammer

A Jammer is the Wave Change of a Human and an EM virus in MegaMan Star Force. FM-ians pick a human to infect with their viruses and then they dispatch a virus to that human. The virus has more control in the body than the human host.

In the game
Early in the game, an unknown Jammer appears inside a Comp Space of a car parked near the condo in Geo Stelar's neighborhood of Echo Ridge. Omega-Xis sensing the presence of an enemy FM-ian, instructs Geo to seek it out. As Mega Man, Geo eventually finds and defeats the Jammer (who was just a car thief), initially mistaking him for the FM-ian they were searching for.

Sometime later, another Jammer appears and drops a chandelier on Geo at school. He fights and defeats Mega Man, being the first boss to do so. The same Jammer reappears in the Libra Scales incident; however, this time Mega Man won with the power of the Star Break.

Three Jammers appear in the Time Square Wave Road, distributing Gemini's Ultrasonic waves to make Brothers fight. Again, they were defeated.

Later, after Geo and Omega-xis had separated, three Jammers beat Geo to a pulp, but the Satellite Admins arrive and delete them. Sometime later, a guardian Jammer was hit by one of PitcherMan's baseballs when Geo tried to reunite with Omega-Xis.

In the anime
In the anime, Humans are not transformed into Jammers, rather they are turned into a humanoid version of the virus itself, such as a McCleaver merging with an artist.