It's not all bad when Jim and Leonard awake in a strange room containing a large pool of water - until the tentacles start appearing.

On an exploration mission to Elissinar IV, Kirk talks Sulu into letting Dirandae, one of the President's aides, take them back to her room to "look at a plant". It turns out the Elissinar have entirely different sexual organs from Terrans. Hey, exploration missions can be fun!