Invincible Season 4 Sneaks In A Clever Transformers Easter Egg Most Viewers Missed
Invincible’s penultimate episode of season four hits like a meteor, as Mark Grayson’s showdown with Thragg ignites the Viltrumite war and a shattering final twist drops. Along the way, the series rips open the empire’s brutal origins with its most devastating look yet.
Invincible just dropped one of its heaviest hours of the season, and it snuck in a very nerdy surprise: a straight-up voice-actor reunion that pairs Optimus Prime and Megatron in the same scene. Yes, really.
The penultimate punch: brutal battles and a deep-cut flashback
This week’s penultimate episode ramps up Mark vs. Thragg and the Viltrumite Empire, and it caps off with a pretty devastating reveal I won’t spoil here. Along the way, the show slams the brakes for a flashback to the early days of the Viltrumites. We see the old ruler, Argall, on the throne; Thragg serving as his right-hand enforcer; and Thaedus, who at this point is still inside the Viltrumite machine, quietly trying to lower the temperature before the whole thing boils over. It’s a harsh look at how Thragg climbed to emperor by building a culture where only the strongest lived long enough to matter.
Wait, was that Optimus and Megatron?
Here’s the fun part. Argall is voiced by Frank Welker. Thaedus is voiced by Peter Cullen. If that pairing made your ears perk up, you’re not alone. Fans clocked it fast on social media (one post on April 15, 2026 put it perfectly), because that’s Megatron and Optimus Prime sharing the screen again — just in very different bodies.
- Frank Welker voices Argall here; you know him as Megatron in Transformers and, among a million other roles, Scooby-Doo, Garfield, and Fred from Scooby-Doo.
- Peter Cullen voices Thaedus; yes, that Peter Cullen — Optimus Prime himself. In Invincible, Thaedus is the Coalition of Planets leader who once stood inside the Viltrumite ranks.
Could we get a full-on Transformers reunion soon?
Maybe. Robert Kirkman is shepherding an animated adaptation of Skybound’s Energon Universe — the comic line that brings Transformers, G.I. Joe, and other Hasbro staples under one roof. There’s no release date yet, but it’s easy to imagine Welker and Cullen suiting up as their signature robots if scheduling and contracts line up.
"It’s not like Hasbro came to us or anything, Hasbro was going to other publishers, and publishers were putting presentations together. We were scrambling because we didn’t know it was available. We came in at the last minute, put together a presentation, and went all-out. We got lucky enough to secure the rights. I feel like it’s working, and it’s a passion project for all of us. We’re excited to work in this universe. There’s not much business planning with all this; it’s very much creative and fun first."
The finale setup: Viltrumites inbound
There’s one episode left this season, and the Viltrumite Empire looks like it’s heading straight for Earth. Considering Omni-Man and Conquest alone carved a path of destruction the last time they visited, a full Viltrumite arrival is terrible news for Mark and anyone who likes the planet in one piece. Buckle up.