Lesla-Lar
Lesla-Lar
An exact double of Supergirl and a jealous Kandorian scientist who constructs a device that sap's Supergirl's powers so that she might take her place (Act No. 279, Aug 1961: "Supergirl's Secret Enemy!").
Though Lesla-Lar's diabolical switch is discovered in time (by Krypto) and she is ultimately sent back to Kandor (Act No. 282, Nov 1961: "The Supergirl of Tomorrow!"), later, she foolishly allies with three Phantom Zone criminals who turn on her and use a powerful Kryptonian weapon to vaporize her (Act No. 297, Feb 1963: "The Forbidden Weapons of Krypton!").
The psychic energy of Lesla-Lar apparently survives as many years later she attempts to inhabit Supergirl's mind (SF No. 206, Mar/Apr 1981: "Strangers at the Heart's Core!").