Outlines are features in mope.io. Your animal has a dark green outline, while animals that you can eat have a light green outline. Animals that can eat you have a red outline, and sometimes with a glowing green tail, meaning you can tail-bite them. You can eat animals with a light green outline. An Animal with a dark green/blue/gray outline can't eat you but you can't eat them.
- On March 14, dark green outlines in Ocean were changed to blue and dark green outlines in the Arctic were changed to gray. Land animals have a Dark Green Outline.
- Outlines used to be in the older logo of Mope.io as if Pike's old logo used to have a red outline for the dragon and a light green outline for the mouse, but that was fixed in the final logo, since Dragons can't eat mice!
- Food also have outlines to tell if it's edible or not, but food never has a red outline. (Food can't eat animals, that would just be weird!)