Vin Diesel fuels Guardians of the Galaxy spin-off speculation with new Groot artwork

Vin Diesel has been teasing fans of a Guardians of the Galaxy spin-off film, The Arbor King, for quite some time now, and he has shared the latest update. For months, Diesel, who voices Groot in the MCU, has been teasing that a spin-off focusing on a different version or ancestor of the character might be in development.

At San Diego Comic-Con and D23 2026, Marvel has revealed a variety of future projects that are in development, but The Arbor King isn't one of them. However, Vin Diesel's new update has increased curiosity around the rumored project.

Vin Diesel's newest update on the Guardians of the Galaxy spin-off, The Arbor King

Vin Diesel has recently made a post on Instagram that includes two images and an intriguing caption. The first image is of a large and fierce version of Groot, and the next image seems to be concept art of a comparison between the enlarged Groot and what it may look like to announce The Arbor King at Hall H.

The post is captioned as

The cast of... Wait... he's too big for Hall H...

It looks like Vin Diesel is saying that The Arbor King would've been announced at San Diego Comic Con's Hall H this year, but this version of Groot is too large to fit in the venue. Not much about the status of the project can be understood from the post. However, it seems like something might be announced at the next San Diego Comic Con. While that is a year away, MCU fans might just have to wait that long.

So far,The Arbor King is a concept title teased by Vin Diesel on social media for months. Marvel hasn't said anything about the project yet. Diesel has been teasing it as a potential standalone or spin-off based on Groot. In Marvel comics, Groot is a Flora colossi from Planet X. That planet is ruled by an elite governing class known as the Arbor Masters.

According to Marvel Comics,

"Together, these leaders teach children—called saplings—via a method known as “Photonic Knowledge.” In this process, the accumulated knowledge and experience of generations of elders gets psychically absorbed by the young through a kind of photosynthesis; this ultra-advanced educational practice provides the Flora Colossi with genius level intelligence."

This class is also known for enslaving small squirrel-like creatures called the Maintenance Mammals. The Arbor Masters treat them extremely poorly, and Groot, who finds friends in the Maintenance Mammals, does his best to protect them.

Besides, Groot has royal lineage connected to the title of King Groot in the comics. Groot's history in the comics is thus a rich one, and there's a lot about him and his species in comics that can be explored in potential projects. Since Marvel hasn't hinted at anything, Diesel's tease seems to hint that the upcoming project, if it is really happening, might follow an alternate alpha version of Groot or an ancestor of him.

So far, The Arbor King is just a tease and speculation fueled by Vin Diesel. It definitely has the chance of becoming a film in the future, but there aren't any official confirmations from Marvel yet.

Stay tuned for more updates.