ZID controller reported an airborne conflict with a mode-C intruder.

Attributes
ACN	1658001
Time
Date	201906
Local Time Of Day	1201-1800
Place
Locale Reference	ZID.ARTCC
State Reference	IN
Aircraft 1
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 121
Flight Phase	Climb
Route In Use	None
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Deviation - Procedural Published Material / Policy

Narrative:

A mode C intruder popped up on airspace at FL300. This started a conflict alert with aircraft X and another aircraft already talking to [another sector]. I turn aircraft X 15R to avoid the mode C intruder. After I was clear of the conflict I turn aircraft X back to [their destination]. I watch the mode C intruder descend from FL300 all the way down to 100 MSL and the track moved very little (seem to hover). At this point I dropped the track.

Original NASA ASRS Text

Title: ZID Controller reported an airborne conflict with a mode-C intruder.

Narrative: A Mode C intruder popped up on airspace at FL300. This started a conflict alert with Aircraft X and another aircraft already talking to [another sector]. I turn Aircraft X 15R to avoid the mode C intruder. After I was clear of the conflict I turn Aircraft X back to [their destination]. I watch the mode C intruder Descend from FL300 all the way down to 100 MSL and the track moved very little (seem to hover). At this point I dropped the track.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.