In the northwest section of Animal Well, there is a Bat Boss fight that you can discover. While this fight is actually fairly simple to win, that's only true if you understand what tools you need to be using and come prepared to beat the fight.

How to Beat the Bat Boss

In order to beat the Bat Boss, you will need to have three firecrackers and a match. Basically, you need to light the candle in this room to activate the boss fight and then use the three firecrackers to scare it away. You will want to space out the firecrackers by a few seconds, just to make sure they all count, since you can't bring a spare firecracker in this case.

The Bat Boss is located where the red skull icon is in the above image. The room directly to the left of the boss fight room contains three firecrackers and can be reached by destroying the rock in the top right corner to head that way. The boss fight doesn't start until you light the candle, so don't do it until you are ready to fight.

If you don't have a match handy, the closest one can be found four rooms to the right. In that room there is a five-by-five maze that you can navigate, with the match in a chest in the bottom left corner of that maze.

Once you have all the necessary materials, return to the boss room, light the candle, and throw out the three firecrackers, making sure to space out each one by a few seconds. Once the third goes off, the Bat will fly away. There isn't a reward for doing this, but it does mean you can explore this room without being hassled.