Jamacy (ジャマシィ Jamashī) is a small guard robot enemy in Mega Man 3 created to keep-off intruders. A single Jamacy that moves up and down a ladder appears in Snake Man's stage and in the Doc Robot Spark Man stage. They also appear in the Doc Robot Gemini Man stage, where they emerge from holes in the field and scurry about on the ground, climbing down ladders in their path.
- Jamacy's name is probably derived from "jama", Japanese for "hindrance".
- Jamacy is called "Bug" in the Nintendo Power issue #20.