Graphite Bloon

Graphite Bloons have the same properties as lead, except for a two special things...
 * 1) Graphite Bloons leave a black trail wherever they go.
 * 2) If a bloon touches a Graphite Bloon, it is temporarily sped up, because rubber moves faster when touching carbon graphite is a really good lubricant.

Trivia

 * Graphite Bloons appear to be responsible for for the Bloonish writing on Bloon notes (Creep said that these are upcoming.).