Nightmare Police

The Nightmare Police (ナイトメアポリス) is a group composed of two Reploids, Bit and Byte, formed by Dr. Doppler to protect Dopple Town.

Mega Man X3
They appear in the eight stages from Mega Man X3 to stop X in free sub-bosses room. If they aren't both defeated with their weaknesses, they will combine into Godkarmachine O Inary in the first Doppler Stage.

Rockman X3 manga
The Nightmare Police are two Reploids upgraded to have their bodies made entirely of Worms, granting them great power and allowing them to dismantle their bodies and move like Worms. Dr. Doppler only sees them as experiments, having no attachment to them and attacking them alongside X due to them being on his way. As they survived, Doppler decided to use Worms to upgrade them into "a powerful tool", turning them into Godkarmachine O Inary against their will.

Rockman X Giga Mission
Isoc studied Dr. Doppler's works related to the Limited and upgraded it, now calling it the Extreme. He then created two Reploids from data of Doppler's Nightmare Police and the Extreme, Sakitira CC and Pranara DD, and ordered them to search for Zero.