Residents were left puzzled after a bubbling brook turned blood red last week.
Rumours were rife on Facebook as to what had caused the water to turn a deep shade of crimson.
Locals in Northamptonshire compared it to a scene from a horror film - with some fearing it was a sign of the apocalypse.
One commented: "The start of the book of revelations. Thou local waters will turn red like blood is the sign of the coming of the Anti Christ."
Pep Finn-Scinaldi, 28, from Northampton, who lives close to the brook, said : "At first I thought something had died as it looked like blood but when it was all the way along we said it must have been a whale to create that much blood."
But the reason behind the discolouration of the stream near the A43 in Moulton, Northamptonshire, turned out to be a lot less dramatic.
An investigation by the Environment Agency found an ink spillage had caused the water to flow red.
A spokesman for the agency said: "The water has returned to its natural colour and, apart from the discolouration, we do not believe there were any negative environmental effects.
"We have worked with Anglian Water to trace the source of the red colouration through the surface water drains.
"As a result, we found the source to be a spillage of red ink.
"The watercourse affected was a small stream that is a tributary of Billing Brook, in Northamptonshire.
"The red colour was caused by a water-based ink which has no environmental impact."