Todd Kenreck: Mordenkainen's Tome of Foes introduces the Oblex. It is a terrifying monster that is now one of my favorites in the D&D multiverse and is the brainchild of one very imaginative boy. There's a new type of creature in Mordenkainen's Tome of Foes, the Oblex. How did they come about and what different types are there?
Jeremy Crawford: While we were working on Mordenkainen's Tome of Foes, we had a special visitor. Nolan Whale, a boy who's a part of the Make-A-Wish program, his wish was to spend the day with us working on D&D. We were delighted and honored to say yes to that and to have him spend the day with members of our team, working on various things, concepting various things. One of the bits that arose from that day with Nolan was this monster, the Oblex. Nolan had this idea of this creature that was the result of Mind Flayer experiments on oozes. Mind Flayers of course are responsible for many sins in the D&D multiverse. I mean, they are in some ways one of our worst villain groups because of all of the harm they have done to other peoples, to various species in the different worlds. D&D history is littered with the evil of Mind Flayers. Now, we get to add something to their list, the Oblex.
They manipulate oozes to create these creatures, the Oblex, that can absorb the memories of other beings and not just the thoughts. Once they've absorbed those memories from someone, they can then create a duplicate of that person tethered to a essentially this umbilical cord of ooze behind them. An adult or Elder Oblex can actually carry within itself basically the memories of a host of people and cause versions of those people to pop up. I'm imagining once a group encounters several of these people formed by an Oblex, they're going to start having paranoia in future campaigns and often want to look behind NPCs they're talking to to see is there sort of a slimy umbilical cord attached to them in back to see if they're actually a Oblex.
We also in Mordenkainen's Tome of Foes talk about the younger Oblex Spawn. They are the result of actually an older Oblex being so filled up with people that essentially the memories sort of blorp out of the larger ooze and then start creating these smaller ones. It's really some fabulous horror movie kind of stuff, of these oozes that go around and steal people. It's very kind of invasion of the body snatchers-esque, and then can haunt communities with memories of these people in physical form. I think they're going to be some really dark tales that people will be able to tell in their adventures using this Oblex, thanks to Nolan.