Legends Class Optimus Prime is based on his original Generation 1 appearance. He features a fake grill for his robot mode, and his large legs result in a fairly thick and compact truck bed. He is part of "Reveal the Shield", a subline that outfits all its toys with rubsigns, and in this case, it's located on the left side of the truck/his left elbow.
If Optimus ordered his troops to come to the humans’ aid, they found themselves taking part in a struggle in futility, as the entire town was near-weightless, meaning they couldn’t put the humans anywhere where they wouldn’t float away once more. Then, the Autobots heard Decepticons approaching. Helpless in their current position, the Autobots were quickly eradicated by the Decepticons.