Crazy Awesome: Bjorn the Bear, a sentient bear who can talk. He was kept as an abused pet/slave of Morinth until Shepard distracted her during Samara's Loyalty Mission; he broke free and mauled Morinth to death afterwards. He then proceeded to set up his own base of operations on Omega. Also, he thinks that all Asari are Dark Elves and feels that he owes a debt to Shepard.
Hilarious in Hindsight: You can find a report in Mass Effect 3 of a Cerberus operative's ocular flashbangs actually making someone's head explode, just like in the fic.