Nuggs

Nuggs are large spherical birds that look similar to balloons. When they are attacked, they will swell up and eventually explode. They appear in various colors as powerups in Battle Bears BLAST and Battle Bears Zero and as a Defensive Tower in Battle Bears Fortress, but also make a cameo appearance in Battle Bears Gold as well as being shown as part of the Battle Bears Comics, living on the Huggable Planet.

In Battle Bears BLAST
There are four variants of Nuggs, with each colour granting a special ability.

Purple:  Doubles all points earned for a limited time.

Yellow: Awards extra points the longer it's targeted. It takes longer than usual to kill.

Blue: Slows down all Huggables for a limited time.

White: Turns all huggables white for a limited time. This is to allow more points through combos, as white counts as neutral.

In Battle Bears Zero
There are three variants of Nuggs, each adding a set time to the clock and boosting the point multiplier to x5. A bird noise is made before each appear on screen.

Blue: +10 seconds. Are slow and large. 

Yellow: +20 seconds. Medium speed and size.

Black: +30 seconds. Are fast and small.

In Battle Bears Fortress
In Battle Bears Fortress, the Nuggs appears in the form of a Defensive Tower which costs 20 Joules. Upon placement, it flies forward in the lane and defecates on the lane. The faeces are temporary and direct Huggables onto another lane. The tower itself cannot be destroyed.

Official references
This page was officially referenced by www.omaha.com on December 19, 2012, describing the characteristics of Nuggs when writing about the success of the Battle Bears franchise and the billboards around Omaha with Nuggs on them (although the art resembles SkyVu's game RainBlow, which technically isn't directly linked to the Battle Bears universe). See it here: www.omaha.com/article/20121219/MONEY07/312199828