"No! NOOO! Optimus, don't die!" The small, yellow 'bot cried. Opimus' spark sank at the sight of his most faithful companion, in such a state of sadness. Optics glazed, pain and hurt emitting from them in such copious amounts, it was almost palpable. Optimus extended a hand, cupping the little 'bot's cheek. Feeling the warm—what were they referred as?—tears that streamed down Bumblebee's faceplate touch his thumb, Optimus smeared it away, softly whispering,
"Do not grieve for me, Bumblebee. There's-"
"How can I not!" Bumblebee screamed, his voice breaking at the last word. Bumblebee held his leader's hand in place, his tears now cascading down his faceplate; his optics had flickered offline. "I love you." The 'bot barely breathed out. Optimus gazed upon the sobbing little Autobot, thankful that his spark could be lifted so highly before it gave out completely. Softly smiling under his face plate, Optimus tenderly replied,
"And I you, little one."
Bumblebee gazed up upon his dying leader, his own optics glistening with sorrow, and a broken smile upon his lip components. He shifted his head so that his lip components met Optimus' palm, and kissed it once, before the warmth beneath the metal exterior slipped away from him forever.
One-shot only. Sorry guys. I always imagined this happening in G1, but certain things are sorta out of place for that, so feel free to imagine whichever continuity you want, since I didn't technically give explicit descriptions on their appearences. Inspired by a picture called "Transformers Too Late" on Deviantart (by PritzPritz)