What are Comet Tails?

My favourite comet was Hyakutake. Firstly it put on a great show visible from the dark skys where I lived at the time (Donegal Ireland) nd secondly as it inspired the name of my favourite dog. See his story here. <a href="https://rnli.tributefunds.com/fund/Comet+Hyakutake/showFund/" rel="nofollow noopener" target="_blank">https://rnli.tributefunds.com/fund/Comet+Hyakutake/showFund/</a>