Sleep Talk

Sleep Talk is a move that can only be used while a pokemon is under the sleep status. The ability will randomly use one of the pokemon's other attacks. It is a good ability when combined with a pokemon who knows Rest as you can slowly recover health with still attacking.

Where to Find
In Gold/Silver/Crystal series it can be found in the underground passage in Goldenrod City.

In Diamond/Pearl/Platinum it can be found in Eterna Forest.