Prime's death in ROTF. I remember how intense the scene was for my 13 year old self. Even my parents didn't like it. I mean getting stabbed in the back and out the front then having your chest blown out only seconds later? I mean damn. DOTM, for whatever reason, lost me on the emotional appeal. But I was spoiled shitless before I even saw it in theaters so that explains why. AOE: Lucas's death did it for me. It was the first human death of a side character, and it was the also the first one to be really focused upon. Between his charred corpse, the music, and the other protagonists actual reaction to it just makes it the most eerie scene in the movie, and just as eerie as the Chicago Invasion.
Ratchet's brutal death is pretty horrendous to say the least. Not only was having his spark ripped out bad enough but then to have his head melted down was just a 'WTF?' moment.
Guys I think BB will be killed next movie because in each movie one of the original Autobots have died: Jazz-TF1, Prime-ROTF, Ironhide-DOTM, Rachet-AOE. So BB will likely be the next to die and maybe revived.
More like I wish. But we all know Bee has that invincible plot armor so....he will never die. Period.