Strange
Cybertronians had never been known for any sort of love for organics of any species, so it was expected that newly arrived Autobots would be surprised to find that their comrades had allied themselves so fiercely with the human race.
Stranger still was the fact that they had actual affection for a number of them, especially the one called Samuel, the bond- brother to both Optimus and Bumblebee, the organic Prime.
It was unheard of for Primes to exist outside of their species, but there was no denying that is what he was.
Despite that, it never took long for them to understand why he was so cared for by the others, or for them to form their own attachments to him.
He loved the Autobots as much as they loved him, willing to fight like hell for them without any hesitation, unlike so many others of the humans who feared them.
He wasn't the smartest or bravest of his race, he was really rather odd when it came right down to it, but he certainly was the most cherished.
Sam was a strange organic, and that was why they treasured him so much.