Conrad Carapax's rival Dan Garrett died as the Blue Beetle on Pago Island, at the hands of Jarvis Kord's robots. His friend Ted Kord, who was with him, was the one originally to convince him to investigate Pago Island, and also the nephew of Jarvis, promised to take up the mantle of the Blue Beetle. A long time later, Conrad, who was jealous of Dan, went to Pago Island to find out what was so important on that island that Dan would risk his life. After months of searching, he discovered Jarvis Kord's laboratory. In a fluke accident he transferred his brain into one of Jarvis Kord's droids by touching a wire. This is how he became Carapax the Indestructible Man.
He stayed on the Island until Chicago Police Lieutenant Maxwell Fisher led a search party to investigate what he thought was a cold case murder of Dan Garrett. Carapax attacked and killed everyone except Fisher, who was saved by the second Blue Beetle. Carapax was defeated by dropping him into the Atlantic Ocean. This however didn't work. He just simply walked for months underwater until he entered the St. Lawrence Seaway, and came across Blue Beetle's secret lair in Lake Michigan just outside of Chicago. This time the Blue Beetle had to crash his Bug Ship into Carapax and detonate it, in order to defeat him. Years later however Neron offered him powers in exchange for his soul. Carapax however refused. Later, some aliens found him and transferred his essence into another droid before leaving him again on Earth.
Superman: Back in Action
For more information see: Superman: Back In Action
After One Year Later, Superman and Firestorm paired up to stop Carapax; Firestorm was about to vaporize the robot, but was stopped by Superman, who explained Carapax was the robot, not a human inside a battle suit. Firestorm converted half his circuitry into germanium, rendering him immobile.
Much later, Carapax was converted into a steampunk-style machine, in order to make him more resistant to technological strikes. The new Blue Beetle, Jaime Reyes, defeated him nonetheless by using his own missiles against him.
There were multiple Carapax units used against the Suicide Squad
used on an island where the Board of Directors Haake-Bruton Headquarters were. These ubnits looked similar to the original suit of Carapax armor