Rex, the Wonder Dog was used as a test subject for a super-soldier formula during World War II. After being injected with the drug, he gained human-level intelligence. He served in the US Army's K-9 Corps.

Fountain of Youth

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Rex and Bobo are reinvigorated by the Fountain.

During an adventure with Detective Chimp, they tailed some thieves who had robbed a circus, to the Atlantic Island of Bimini. When an alligator attacked Bobo, Rex defended him but was wounded. Bobo went off and found a source of water that turned out to be the fabled Fountain of Youth. The water reinvigorated them both, returning their youth and extending their lives.[1]

Further Adventures

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  • Although this character was originally introduced during DC's Earth-One era of publication, their existence following the events of the 1985–86 limited series Crisis on Infinite Earths remains intact. However, some elements of the character's Pre-Crisis history may have been altered or removed for Post-Crisis New Earth continuity, and should be considered apocryphal.
  • Rex is also known as Wondrous Rex, and the Wonder Dog.