The Transformers cartoon
After Spike Witwicky and Carly arrived at Decepticon Headquarters on Cybertron via Space Bridge, they quickly managed to escape from Shockwave's control room. The guardian of Cybertron then dispatched "the Sentinel", a treaded robot with pincer-like hands, to deal with the humans. Thinking fast, Spike crushed its head in a gigantic sliding door, destroying it.
Later, when Chromia, Firestar, and Moonracer escaped capture at Shockwave's hand, he sent a different Sentinel, which was capable of flight, after the trio of fleeing female Autobots. Though the wheeled, multi-gunned machine tracked them to the general vicinity of their secret headquarters, this Sentinel was obliterated by a single blast from Moonracer's pistol.
When next encountered, Shockwave had a large group of "Sentinel guards"—of a different make from the last two units—which he deployed in practice military maneuvers with giant holograms. These Sentinels were present when an asteroid arrived on Cybertron carrying the banished Combaticons.
Shockwave and the Sentinels defended the planet from these renegades, who combined into Bruticus and utterly decimated them. A short while later, the Sentinels assisted a joint Decepticon-Autobot task force in defeating the giant Bruticus, although many more were reduced to scrap in the process.
- The Sentinel that appeared in "The Search for Alpha Trion" was actually a re-used robot model from "Desertion of the Dinobots, Part 2". Presumably this means the original robot in DotD was one in a series, as Shockwave disintegrated it shortly after Spike and Carly tried to used it as cover.