The "Halloween asteroid" set to make its closest approach to Earth today has turned out to be something spookier: a dead comet. Scientist say object 2015 TB145 looked like an asteroid when it was first spotted a few weeks ago. but closer inspection suggests that it is a comet that has passed the sun so many times that it has lost the layers of ice that would produce a tail, reports the Washington Post, which calls the visitor a "zombie comet." Radar images from the Arecibo observatory in Puerto Rico are also a little unsettling: The data "may indicate that the object might be a dead comet, but in the Arecibo images it appears to have donned a skull costume for its Halloween flyby," a NASA scientist says. (More asteroid stories.)