The country is on UFO-watch after some apparent sightings in recent weeks.
A number of aircraft off the south-west coast of Ireland earlier this month reported sighting an unidentified flying object in the airspace.
This is what they reported seeing (scroll to 17m to hear interaction):
The Aviation Authority of Ireland has launched an investigation.
The latest sighting was caught in a video which was taken over Spike Island in Cork Harbour by Luke Kelly-Wilmot.
Take a look:
Did you see it?
A black dot on the horizon appears to hover over the former island prison before moving quickly out of the shot.
What do you think? A sign of extra-terrestrial life or just a fly on the window? Tell us in the comments.