Whacka
Whackas are blue mole-like creatures that live on the west side of Mt. Rugged and near the shore of Keelhaul Key, among other areas. Hitting one on the head with a Hammer will make a Whacka's Bump, an edible and valuable item, appear. However, this causes internal injuries to the Whacka. If they are hit too many times, they will die. Since their bumps are so valuable, Whackas are an endangered species and should be treated with care. According to Wonky, there is only one Whacka left in the world. This fact is proven false, however, in Mario Party 6. In the Snowflake Lake level, Whackas can be seen popping up out of the snow.
At one point, the Whacka on Mt. Rugged sends Parakarry a letter stating he one day dreams of flying.
Also a Whacka appears in Super Paper Mario. He also has a Catch Card.
