Yep, the latest injured animal has hit the Frontier and it needs your help to get out of a very sticky situation.
The Brown Mule is discovered when clearing grass or harvesting crops and is stuck in a hole, needing a good yank to free it and allow it to roam your Homestead.
First you need to click the mule yourself to try and dig it out (using up three energy) then it says you're not strong enough and need to get some help!
You do this by requesting (in the same way as asking for blankets or berries) help from your neighbours to pull.
Once out it becomes a collectible animal dropping injured animal collectibles every 24 hours plus the usual mule bonuses.