You just caught Chlamydia! Illustrator Matt Wiley designed these Sexually Transmitted Diseases frisbees as public service ad campaign to raise awareness on how easy catching STDs can be:
The main idea is to throw these (gently) to passers-by on college campuses and to yell, "YOU JUST CAUGHT CHLAMYDIA!" as the individual catches the disk. The back would be printed with contact information either to research the disease on a Planned Parenthood type website or contacting the local Wellness Center.