GO TO VET .... ASAP
Untreated this kills kitties. Sounds like Coccidia which needs antibotics to treat. To much of human tuna can cause runny potty. However, when kitty doesn't want to be bothered with or messed with he/she is ILL and needs to see a vet. That's their way of tell you they are sick since they cant verbally talk to you.

Sorry, putting kitty outside doesnt treat the problem. Please put out bowls of water for kitty. Dehydration is a concern.