'Devil Comet' 12P/Pons-Brooks is approaching Earth. Why is it flaring up, 'horns' and all? 

 The exact cause of 'Devil Comet' 12P/Pons-Brooks' flare-ups is unknown, though the best guess is that perhaps a fissure has developed on the comet's nucleus due to a build-up of gas. 

https://cdn.mos.cms.futurecdn.net/FJSwsvyUH9spEMqcb5nbjE.jpg

https://www.space.com/devil-comet-12p-pons-brooks-approaching-earth