I was working on a model and I THINK I hit ctrl+4 before this appeared, I was trying to change views and hit the wrong keys. What do I do to get rid of it?
Ctrl+4 shortcut adds a subsurf modifier to your object at a level 4 subdivision. You are seeing the subsurfed object inside the original object as the editing cage.
If you don’t want the modifier just delete it in the modifiers panel