Fanner (ファンカー,Fankā?, "Fancar") are a class of virus in Mega Man Battle Network which resemble a large industrial fan with wing-like fins. These viruses, despite the apparent presence of legs, remain stationary in battle, and have an odd switch mechanism jutting from their backs. When attacking, these viruses produce a swirling tornado, capable of moving a set amount of panels, which homes in on the player. Stronger variants produce faster moving tornadoes which deal more damage.
Fanner are red colored fans on four legs. These are the basic and weakest Fanner viruses.
Their whirlwind attack hits up to three panels, homing in on the player.
Fanner 2nd are blue colored fans on four legs. Their attacks have the furthest range of the Fanner virus family.
Their whirlwind attacks have a maximum range of eight panels. When grouped together, their tandem attacks can be very difficult to dodge, as their overlapping whirlwinds might end up cornering the player from any way to escape damage, or even hit all of the player's adjacent panels at once.
Fanner 3rd are grey colored fans on four legs. They are the toughest breed of Fanner viruses.
While Fanner 2nd's attack had a range of eight panels, Fanner 3rd's attack range returns to three panels. However, their whirwind attacks deliver not one, but two hits of damage when they make contact with the player.