The “Pinata” achievement requires players to blow up a Sluggy in Sons of the Forest. A Sluggy is a type of mutant that players can find stuck between cave walls. Players can use a timebomb to blow up a Sluggy.
Finding a Sluggy
Sluggies do not spawn in the overworld nor pose a direct threat to the player. As of writing, they only act as blockage inside caves to prevent players from venturing further. As such, going inside caves is the only way to find them.
The best place to find them is in the Zipline Rope Gun cave in the western part of the map. There is a helicopter crash point just beside this cave which players can use as a reference point.
Simply head into the cave and fight or run through the group of Puffy mutants. Eventually, players will find dead workers, a couple of time bombs, and a Sluggy stuck in a wall. Throw a timebomb toward the Sluggy to blow it up and get the achievement.