Wraith
Wraiths are enemies that were introduced in Wonderland Adventures Planet of the Z-Bots.
There are currently 2 official varieties of Wraiths, the Pow Wraith and the Brr Wraith; the former shoots out Pow, and the latter shoots out Brr.
What sets the wraiths apart from Fireflowers and Iceflowers is that they "activate" and start shooting only when the player steps in range. The range of each wraith is variable, and can be decided by the level maker. Otherwise, they are invisible. Also, destroying Wraiths do not earn the player any additional points, unlike Fireflowers.
Other types of Wraiths, such as Grow Wraiths, were coded into the game, but were not utilised. These wraiths would be available for level designers when the POTZ editor is released.