Yak Shave
Noun · Verb · Slang & Abbreviations · Origin: 2000
Definitions
A single prerequisite task in a yak-shaving chain. 'Updating the SSL cert was a four-yak-shave just to fix the login bug.'
In plain English: One single task in a long chain of prerequisite tasks that has taken you far from your original goal. Each task seems necessary, but you've lost sight of what you started doing.