Blood Rain is literally blood in the form of rain.
In the springtime, Blood Rain showered over LaGuardia International Airport when Louis Tully was picked up by Sherman Tully. During the wedding of Winston Zeddemore and Tiyah Clarke, Blood Rain manifested. The Blood Rain came down on Kylie Griffin as she gave an invoice to Mr. Crook for capturing the Five Points Killer. When Winston and Tiyah had their first dance as a married couple, more Blood Rain began to pour outside. The shower lasted for 45 minutes. Egon Spengler and Ray Stantz took samples and ran an analysis. The next day, they concluded it was ordinary blood. Just in an abnormal circumstance. Later that day, more Blood Rain was sighted in the Columbus Circle area amid strange gravitational anomalies. Meteorologists remained stunned by the intermittent storms over the past few days. The Mayor conferred with the Center for Disease Control on the matter. In the meantime, the St. Patrick's Day Parade was canceled until further notice. After attending meetings all day, Walter Peck went to the Ghostbusters for anything he could take back to the Mayor and prevent a city-wide quarantine from being issued.
After Crossed the Streams on Tiamat, the Ghostbusters found themselves back on the apartment roof and another shower of Blood Rain started. Blood Rain continued to shower over New York City for the next couple of weeks.  The Blood Rain finally ceased once Tiamat vacated the dimension. A short time later, a normal rain storm hit the city.
- Ongoing Series
- ↑ Lou Kamaka (2014). IDW Comics- "Ghostbusters Volume 2 Issue #17" (2014) (Comic p.3). Lou says: "You started talking about regular Blood Rain over the last couple of weeks and something about someone named Tiamat."
- ↑ Tiyah Zeddemore (2014). IDW Comics- "Ghostbusters Volume 2 Issue #18" (2014) (Comic p.12). Tiyah says: "It's not like we can just leave town when it's raining blood and pigeons start heckling."
- ↑ Winston Zeddemore (2014). IDW Comics- "Ghostbusters Volume 2 Issue #18" (2014) (Comic p.18). Winston says: "Well, I don't know about that, but man, -between what happened with Dana and Louis here, and more blood raining outa the sky, I'm thinking our batting average on blowing up Mesopotamian deities might not be as good as we thought."