The Churgurnular is the 4th boss of the game found in level 40.
It's a big bucket with sunglasses and legs that jumps around and throws chicken sticks. You can double-jump below the enemy while it jumps over a gap to get around the combat area. You need to wait next to the red button and press it when the bucket is over the middle gap to have a ball of possums shoot up and hurt it.
On normal mode you need to do it 3 times on hard mode 5 or more times.