After saving Bulkhead from a construction accident, they befriended him and were invited to the Autobot headquarters.
After some initial confusion about no longer being inanimate vehicles, the pair named themselves and quickly figured out how to transform. The first two 'Constructobots', Mixmaster and Scrapper, came to life when two stray AllSpark shards were embedded in a cement mixer and an excavator at a human construction site.
