Mr. Swackhammer (voiced by Danny DeVito) is the main antagonist in Jaden's Adventures of Space Jam.
He is the proprietor of a galactic amusement park named Moron Mountain. He sent the Nerdlucks, along with a list of enemies from the past, to capture Jaden and the Looney Tunes to use for his theme park. So, Jaden and his friends challenged the Nerdlucks to a basketball game. Ultimately, after Jaden and his friends won. After realizing they had the size-advantage over him now, the Monstars turned against their abusive boss, strapped him to a rocket and sent him flying to the moon.
- Mr. Swackhammer will become Jeffrey's enemy in Jeffrey & Friends' Adventures of Space Jam.
- Mr. Swackhammer will return for revenge in Jeffrey and Friends' Storm Adventures of House of Villains.