At the very top of Bitcoins ATH a Bearish Butterfly pattern formed on the 15 minute time frame.
After retracing at a near perfect 78.6% of the initial XA leg, price formed the C point and then pushed up to the entry line at 127.2% of XA.
Price took several tests of the entry line before commencing the sizable move down.
Use the channel link below for video tutorials on identifying, measuring and trading the Butterfly and several other major Harmonic patterns.