Thanos (2003 series) #5

Thanos is trying to be a good guy and is defending the Rigellians against Galactus. He's discovered that Big G's big plan is to use the Infinity Gems to replace the hunger that makes him the Devourer Of Planets. However he's also discovered that Galan is being manipulated by an otherdimensional being (coincidentally called Hunger), and the real result will be allowing that to enter this reality and consume it. Now with only Pip the Troll to help him the Mad Titan must do whatever it takes to prevent this.

The valiant duo teleport aboard Galactus' huge spherical spaceship. Pip goes off to plant explosives in strategic places while T locates G and tries to talk him out of his plan. But he believes that Galan's mind has been tampered with so it probably won't work.

Galactus has the 6 Gems in a Focusing Crux which is now warming up. Thanos enters the chamber and warns him that he's been tricked and begs him to shut the device down. G regrets not killing him (in #3) and prepares to rectify the error. But T strikes 1st and sends his much larger opponent out of the spaceship and across the planet it's hovering over (presumably the remains of Rigel-18). G rises but has lost his helmet and he orders some of his robotic Punishers to destroy his foe. They arrive in time to stop T destroying the Crux. He easily defeats them but that's time enough for Big G to get here. T erects a force field which it takes a while for G to penetrate. But T surrenders and asks only to be heard out.

T explains that a being outside this universe tampered with the data which convinced G that the Gems would do what he expects. And the Crux that G created has interdimensional consequences that have been concealed from him. But T's history of guile and deception make G distrust him. (And G's overwhelming desire to stop eating planets doesn't help either.) Despite T's protestations that he's changed, G thinks he just wants to get his hands on the Infinity Gems again in order to conquer the universe. He considers the Titan beneath his contempt and turns back to triggering the Crux ...

... but is shocked when Hunger emerges from it and thanks him for letting him in to this reality. T recognises it as an interdimensional parasite which starts to absorb G's ship and will eventually do so to the whole of the universe. He tells G to switch off the Crux but the Devourer finds that it doesn't respond to his commands, and neither does his ship. He admits to knowing little of such creatures and so agrees to follow T's lead. At T's urging he blasts the invader. At 1st he seems to succeed but the foe adapts and now feeds on the power. The manipulative Titan admits that he expected as much but the battle has furnished him with data.

Pip contacts T to say that the charges are all planted and he's teleporting away now. The charges explode and the crippled ship crashes to the ground. But Hunger had been aware of everything and knew it wouldn't harm him. G is disappointed with T's plan so far. T had hoped the Crux would have lost the ship as a power source but it didn't happen. So he now tries to destroy the device but H now has it protected by a force field. Galactus realises what he has unleashed as Hunger escapes into the universe outside.