My 12 year old daughter was disappointed after starting the campaign as a druid and then finding they were nothing like the WoW druids she imagined. She was later even more chagrined when a friend dropped in for two sessions and played a high-level druid and was able to shape-change into various animals. Essentially what she wanted. She has already said she wants to play a druid next campaign. I thought this would make a cool end-game reward for helping the Sisters of Battle to defeat the Illithid Space Marine Xallitharid.
Wondrous item, legendary (requires attunement)
The Omnitrix resembles a wrist watch. Its face plate is now square instead of round, and has a white and green color scheme. The faceplate is black with two green stripes forming an outline for the hourglass of the intergalactic peace symbol. When the faceplate is slid back, the Omnitrix’s core is revealed. This item allows the wearer to transform into a beast with a challenge rating as high as your character level divided by 3, rounded down. The item can be used a maximum of 10 times per day and you can not take the same beast form twice during the same day (delineated by a long rest).