A year since the end of part II, TOM and Sara are still on Shogo 162 boardcasting the Toonami block from the planet while hoping for any nearby rescue. However one day while milling around, a vicious sandstorm sweeps through the planet with TOM barely able to get back to base in time. However it turned out that the planet, which Sara and he though uninhabited, happened to be the home of native sand worms who follow him back to base. Thus TOM once more finds himself tangling with unwanted intruders.
The series was announced at Anime Expo '16, and was teased further with block bumpers which revealed that new Clydes were built shortly after TOM crash-landed on Shogo 162, recovered SARA, and established the Vindication as the new base of operations for Toonami. On October 14th of 2016, another teaser was shown on Toonami Pre-Flight, with SARA noting seismological disturbances and a massive storm brewing on the planet.
It was announced on Toonami Pre-Flight that, after the conclusion of The Intruder III, a comic (for which Jason DeMarco shared a piece of rough art on Twitter) will be released at the end of November. The comic, named Trapped, will take place before the events of The Intruder III and will chronicle one of TOM's adventures on Shogo 162.
The Intruder III provides examples of:
- All-CGI Cartoon: Animated in the same CG style as the block bumpers, as with past T.I.E.s.
- Big Storm Episode: This T.I.E. stands out from the others due to involving a natural disaster, a storm in this case.
- Bittersweet Ending: Good news: TOM and SARA survive with the help of the Sand Worms, who were merely try to warn TOM and SARA, and the base is actually a ship called the Vindication, meaning they can finally get off the planet and resume their travels. Bad news: the planet dies and all but one of the Sand Worm creatures die with it. But TOM and Sara agree to take care of their youngest and gain a new friend in the process.
- Contrasting Sequel Antagonist: Despite the title, the "good" old Blob Monster doesn't return for a Rule of Three. Instead, TOM now faces giant Sand Worms who are Good All Along and trying to warn him and his crew about the real threat: an impending Earth-Shattering Kaboom.
- Darker and Edgier: The teasers still indicate that TOM and SARA might have bigger things to deal with this time around, such as earthquakes, massive storms, and giant creatures burrowing through the planet. This ends up subverted near the end however. While there is a danger present it isn't from the worms, but rather the storm. Compared to the second Intruder mini-series, this is more Lighter and Softer.
- Deadly Dust Storm: The storm in question, since there's apparently no water present on the planet.
- Foreshadowing: One of the bumpers before this event featured Sand Worms that's be the basis for this one.
- Facepalm: TOM does this when SARA tells him that an intruder may have breached a part of the base they haven't explored yet.TOM: Oh, right... of course we do.
- Flat "What": TOM's reaction when he finds out the base that they've been in for more than a year is actually a ship.
- Good All Along: The worms turn out to be friendly and were actually trying to warn TOM and Sara of the planet's destruction.
- Heroes Gone Fishing: TOM is sunbathing at the beginning of episode 1, apparently not listening to SARA's weather report.
- Informed Attribute: TOM claims to have a very nice singing voice. The karaoke machine didn't seem to agree.
- Kaiju: One of the bumps reveals a creature as big as a mountain burrowing through the ground.
- Lampshade Hanging: Twice in this T.I.E. so far, once about TOM and SARA constantly having to deal with intruders, and another about TOM's weapon never working against anything after getting off a few shots against the sandworms.TOM: Just once, I'd like a blaster to be enough.
- Last of Its Kind: The baby sandworm rescued by TOM and SARA.
- Let Me Get This Straight...: In episode 4, what SARA said is recapped through this by TOM.
- Noodle Incident: The first episode reveals that TOM was using a karaoke machine the night before. Based on what TOM says, it insulted his singing voice.
- Oh, No... Not Again!: TOM's reaction is this when Sara explains that there's an intruder in the unexplored sectors of the station.
- Our Fairies Are Different: In order to escape the dying planet with TOM, SARA upgrades herself to a mobile form resembling a fairy.
- Remember the New Guy?: Clydes have always been a part of Toonami, but the new Clyde models shown in the bumpers were introduced at Anime Expo '16 with no explanation for how they actually came about.
- Sand Worm: The "intruders" of this event. Two of them attack TOM outside of the base. Thanks to an automatic defense system that kicked in, he just barely managed to get back inside. Several more managed to breach the lower sections of the base. Turns out they were only trying to help TOM and SARA.
- A Storm Is Coming: Literally; there's a huge storm brewing, and it's an important plot point.
- Tempting Fate: TOM comments about how the weather is nice enough to go out and explore the planet, just a moment before a storm picks up. He immediately lampshades how he just had to say that.
- ONLY Toonami.