Grumblebug

The Grumblebug is a Petpetpet, which makes grumbling noises. Petpets with Grumblebugs get scolded, often because the Grumblebug makes them grumpy, or their Neopets think that their petpets are grumpy due to the unexplained noise. The Grumblebug is featured in a Petpet Supplies item called Grumblebug Water Bowl, which is said to appeal to grumpy Petpets.