Star Trek: The Next Generation – Rascals [6.7]

A transporter accident causes Picard, Guinan, Ro and Keiko O’Brien to materialize on board the Enterprise transformed into 12 year old children, though still with their adult intellects. 

Star Trek: The Next Generation – The Perfect Mate [5.21]

The Enterprise transports Kamala, an “empathic metamorph” with the ability to transform her personality to become any man’s perfect woman.  Kamala is meant to be a gift for a planetary leader to help secure a treaty, but her presence on the Enterprise causes havoc amongst the men of the ship.