She is an animatronic that was created by Swordyswords189 and be his favorite character in the game.
She was originated in Swimmen on the Seas.
Swimmen is a tall,light blue animatronic with a similarly colored torso,waist,arms,legs and head.She wears what appears to be a ripped brown tank top which exposes her chest.Her head is shaped like a teardrop which matches her identity as a waterdrop animatronic.Her feet appear to be oddly made,which five or four toes are hardly visible,presumably from the lack of effort Swordyswords189 had put into her model.Hence the feet of Swimmen are poorly detailed.She also appears to have a curvy body,which can be seen.
She also appears to be relatively undamaged (excluding her brown tank top) unlike her counterpart Pinky,who is more damaged.
Her endoskeleton shoulders can be partly seen in the extras menu,covered by shoulder plates,along with her eyes and eyelids as well.Her body is noticeably is made of plastic,resembling the Toy animatronics from Fnaf 2.
She appears to have rounded hands with no fingers,curved arms and her upper suit legs are thicker than her lower suit legs,possibly to emphasize the fact that Swimmen is female.Her appearance overall resembles Toy Chica as both have curved parts on their limbs.
It is unknown what night Swimmen starts.Although she is assumed to start on any night when the temperature starts to decrease.However,she presumably starts from the Stage where she crawls in the Right vent to get to the office.If the player successfully managed to seal the vents,she will return to the Stage and repeat her cycle.When she is in the vents,one of the monitors behind the player with show Swimmen crawling in the vents.