What does a bonk feel like?

I had thought I had bonked a few times until I really bonked the first time I did the Tahoe Trail 100. Thought I was doing fine with food and hydration until about 10 miles from the finish starting the last climb back to Northstar. Was climbing along and then out of nowhere I had nothing…my hr spiked, my arms and hands went numb and I could hardly move. I had to get off and sit in the shade…I had a gel and some electrolyte drink and tried to ride…all I could do was crawl along. If somebody would had offered me a ride back I would have taken it. I ended up finishing but felt like crap for a few days.