There is currently a magnetic storm hitting Comet Catalina.
The storm is clearly visible in the sinuous blue ion tail of C/2013 US10 as giant blobs of plasma are forming as shown in this awesome picture captured by Michael Jäger on December 11, 2015.
Plasma blobs in comet´s tails are a sign of stormy space weather which frequently form in response to CMEs and gusts of solar wind.
In extreme cases, a comet’s tail can be completely torn off.
As during terrestrial geomagnetic storms, magnetic fields around a comet bump into oppositely-directed magnetic fields in a CME.
The resulting burst of magnetic energy can make waves, blobs, or even ruptures in the comet’s tail. In contrast, when CMEs hit Earth amazing, they power amazing aurora borealis or australis.