The laka was a bug found on the planet Arnessk. Its intestine contains a substance that acts as a powerful mind-deadening drug; according to Utu-Noranti Pralatong, just "...stick it up your nose! You'll get a jolt – wham! And for five hundred microts nothing bothers you."
Later, Noranti provided Crichton with "distillate of laka", made from the substance produced by the bug, so he could forget the pain caused to him by the presence of Aeryn Sun.