During the Dance of the Dragons, Caraxes killed and was killed by Vhagar, last of the three original Targaryen dragons and largest living dragon during the civil war, in the Battle Above the Gods Eye.
In the books
In the A Song of Ice and Fire novels, Caraxes was one of the older and larger dragons during the Dance of the Dragons. His scales were colored red, leading to him being called "the Blood Wyrm".
Daemon Targaryen rode Caraxes in his frequent campaigns in the Stepstones. As a result Caraxes was not only one of the larger dragons during the Dance, but possibly the most battle-hardened and experienced in war. Indeed, only Vhagar had ever been ridden in major wars before, due to the eighty years of peace the realm had enjoyed since King Maegor the Cruel died - and Vhagar, while formidable, had not been used in combat in the years leading up to the Dance, the way that Caraxes was. Opposing armies were known to often simply flee when Caraxes approached.
When Rhaenyra captured King's Landing in a surprise attack, Daemon rode Caraxes in the assault while Rhaenyra rode Syrax.
Later in the war, Aegon II's younger brother Aemond Targaryen resorted to a one-man war riding Vhagar, burning out much of the Riverlands. Daemon hunted him for a long time on Caraxes, aided by the dragonrider Nettles on Sheepstealer, but eventually he returned alone to Harrenhal (which Vhagar had burned out earlier in the war) waiting as a challenge for Aemond to arrive. Caraxes was formidable but Vhagar was twice his size, nearly as large as Balerion had been during the War of Conquest. Facing him alone was the only way to draw Vhagar out, however, as Aemond had avoided ambushes by multiple other dragons. Aemond arrived, exchanged his final challenges to Daemon, then both took to the air on their dragons.
The resulting Battle Above the Gods Eye was one of the most epic dragon-versus-dragon fights of the entire civil war, as two of the greatest living dragons fought in the air. Their shrieks shattered every remaining window in the castle and could be heard for miles around. Their fire-breath filled the sky so that fishermen in the lake thought that the whole sky was aflame. In the end, Caraxes dove down from the sun on Aemond's blind side (due to his missing eye). Caraxes slammed into Vhagar and they both continued to fight in free fall. Vhagar tore out Caraxes's belly, and used her massive jaws to rip one of his wing-arms completely off - but Caraxes sank his teeth into Vhagar's throat and maintained a death grip. As the two dragons grappled, Daemon rose from his saddle and made a stunning mid-air leap from his dragon to Aemond on Vhagar's back. Wielding the Valyrian steel sword Dark Sister (which had once been carried by Vhagar's previous rider, Visenya Targaryen, Daemon thrust his blade through Aemond's empty eye socket - the force of his impact as he landed driving the sword through the back of Aemond's head. Both dragons plummeted into Gods Eye below. Nothing could have survived the fall and nothing did: Caraxes had ripped out Vhagar's throat and she bore the brunt of the impact, killing her. Daemon's corpse was never found, but Aemond's was found years later with Dark Sister still thrust through it. Caraxes, somehow, was still alive after his massive injures and the fall, but not for long. Missing a wing and with his intestines trailing behind him out of his open belly, he somehow found the strength to pull himself out of the lake onto the shore, where the dragon soon died before the walls of Harrenhal. The battle was a heavy blow for both Rhaenyra's and Aegon II's factions: each side lost one of their greatest champions, as well as each side's strongest dragon. The world has not seen their like again.
Meleys · Meraxes · Morghul · Seasmoke · Sheepstealer · Shrykos · Silverwing · Sunfyre
Stormcloud · Syrax · Tyraxes · Valryon · Vermax · Vermithor · Vermithrax · Vhagar