When you instigate something, you start it, but the word carries conflict with it. If you are suspended for wearing a political t-shirt, the incident might instigate days of protest by students and faculty.
Instigate comes from the Latin word instigare "to incite." People who are instigators often begin trouble but then back off and let others break the rules. If you instigate a food fight in the cafeteria, you might throw the first spoonful of mashed potatoes, but then you stop and let all the other students carry on the chaos. When something is instigated, the outcome tends to be unknown. The plan you instigate might not lead to the desired result.