The Tattoo that Swamp Thing had put on Constantine in Swamp Thing 76 L’Adoration de la Terre was permanently commemorated on my keister today. After Swamp Thing used Constantine’s body to consumate his relationship with Abby, he made sure to leave his mark on John. While in DC, Swamp Thing visited a tattoo shop to get this tattoo.
Although the tattoo never appeared in a Swamp Thing book, it has popped up in a few Hellblzer books, including Hellblzer 232
In Hellblazer 14, The Fear Machine, Part I: Touching the Earth, Constantine learns of the tattoo for the first time from Mercury.