Megatron: Optimus Prime, my mortal enemy, I swear one day I will watch you die! For eons to come I will follow you, I will fight you, and I will witness the years going by and you growing old! And I swear I will always be there, until your very last day when your spark finally goes out, and I swear you will never know a single moment of quiet before that!
Optimus:
Optimus: Are you proposing?
Megatron, with a ring in hand and down on one knee: This is a threat