I don't know if it's been shared here yet, but we have observed evolution from single cell to multicellular life User EvangelineTheodora, in the Dear_Mr_Atheist subreddit, 17 Jan 2020
De novo origins of multicellularity in response to predation User EcoInternetNewsfeed, in the EcoInternet Climate Change and Environment News subreddit, 29 May 2019