I need to read a lot more theory myself, so this is going to be pretty sophomoric explanation, but no one else has answered yet. I hope comrades more knowledgeable about it will correct me and elaborate. I'm also assuming your question is genuine and not an ironic joke that is whooshing over my head.

Anyway, left communism aka ultraleft, like so many other political identifier terms, can be pretty nebulous and vague, where the definition depends a lot on who you ask. But generally, it broadly describes the thought/philosophy of the people who historically criticized Leninism from the left. It's usually critical of vanguardism and any kind of party supremacy/elitism. Bordiga is often seen as the quintessential leftcom. But council communists like Rosa Luxemburg also fall under the umbrella. Whether accurate or not, leftcoms in turn are criticized for being nothing but armchair revolutionaries never affecting any kind of change, but always denigrating the revolutionaries who really did take action. Lenin wrote a pretty famous piece (that I have yet to read) about their folly and what he saw as the flaws in their thinking, titled "Left-Wing" Communism: An Infantile Disorder.