When you start out in Chrono Trigger’s Arena of the Ages you get a puny elemental smidge, but it can grow up and become… a robot? The monster you end up with depends on the time period you train it in. The flow chart shows a Water Smidge trained in the future becomes Version 2.0. Send it to Antiquity, the age of Zeal, and it becomes a Coral Imp. This is only a partial chart so there are more paths for your water smidge and there are other elemental smidges for you to evolve too.
Why bother doing any of this? Square Enix put some powerful items in the Arena of the Ages. One prize is the Master’s Crown, an offensive equivalent of the Prisim Helm. Both items have 40 defense and prevent status changes. However, the Master’s Crown boosts damage instead of adding +9 to your defense.
Images courtesy of Square Enix.