I just read about this that’s apparently a limited time thing, until the end of September.
There are 10 Lion King characters hidden in the Harambe area, You purchase a map at The Outpost Shop or Mombasa Marketplace ($6.99 plus tax) that comes with stickers. (I assume you place the stickers on the map where you find them). Upon completion, return it to Mombasa Marketplace and you get a Lion King character magnet.
Thought it might be of interest to anyone going in the next couple of months. Somewhat less time consuming than the Wilderness Explorers, and contained in one area.
I tried to find something on the WDW website but no luck so far.
And here’s something on the Disney Parks Blog: