Just adding in a better photo from earlier: https://www.reddit.com/r/CODZombies/comments/1pew1xc/is_that_the_ashes_of_the_damned_rocket/
Appeared on round 32 this time, but I think it spawns after round 30 where you have to spend a whole round near wisp tea. I jumped towards the wunderwaf cannon but its too far away.