Time Beetle
The Time Beetle was an insectoid creature capable of manipulating time. It was used by, or was part of, the Trickster's Brigade. With the help of humans within the brigade, or at least a Fortune Teller, it was attached to unsuspecting victims after which it changed a key event in their lives.
It existed in a state of flux which meant that it could not be touched. It was also invisible to humans, except to some extra sensitive ones where the difference between the normal and new timeline was unusually great. It was also visible in the Circle of Mirrors but that may have been due to the time technology that was present.
The Time Beetle attached itself to Donna Noble and in turn created a parallel world around her in which she never met The Doctor. With Rose Tyler's help, she was able to go back in time to the beginning of the new timeline and stop herself from changing it, at which point she was able to free herself of the Time Beetle. It released itself and died from the tremendous force. (DW: Turn Left)
- It is unclear whether the Time Beetle was a sole being or if a race of the beetles exist.
