After the Batman who Laughs and his army of Dark Knights conquered Earth 0 on the behalf of Perpetua, they remodeled the Earth and sent monster creatures from all over the Dark Multiverse to control the planet. Among these creatures, the Creepers, who were themselves an army of Creeper-like soldiers, began patrolling the Slaughter Swamp, using the Grundies as their mounts.
Some time after the invasion, the Creepers met Detective Chimp in the Swamp and attacked him, letting unleashing the Grundies on the monkey hero. Chimp managed to repel the attack by using the mystical Sword of Night but, as he was almost overpowered by the Dark Multiverse fiends, he was eventually saved by the arrival of Nightwing, Hawkgirl and Starfire who defeated the enemies and forced them to run away.
- It was never revealed if the Grundies were once Earth 0 residents that were turned into monsters or they hailed from a nightmare Dark Multiverse reality where they somehow became raging beasts.
- The only words the Grundies were shown speaking was "Born on a doomsday...", an alternate version of the famous Solomon Grundy rhyme.
- 1 Appearances of Grundies (Dark Multiverse)
- Images that include Grundies (Dark Multiverse)
- Team Gallery: Grundies (Dark Multiverse)