SMG4, (best friend) Mario, Woody, Bowser, Bowser Jr., Gaming, Candy, Sweets, Sugary Treats, Chef Pee Pee, (father), Their Mother, YouTube, Helping others, Waluigi, Toadette, (fav. characters respectively) etc.
Being kidnapped, Phillip and Kelly Bomb, Drill Finger, SMG3, The Toddler, etc.
Henry and Samantha are two Twins and are good friends of Bowser Jr. and SMG4. They almost always get kidnapped by an evil villain seeking to rule the Universe and destroy SMG4 and his friends. Most notably Phillip and Kelly Bomb, Drill Finger, The Toddler, and many more kidnap them. Mario and SMG4 always manage to stop them and save Henry and Samantha. They first appear in the Super Mario World Longplay where they were kidnapped by the Phone Shark as a bid to destroy Mario and SMG4's phones. They also sometimes help Mario and SMG4 (one example is in the Super Mario Galaxy 2 Longplay where they have trouble getting one of the Green Stars). They also have a father called Chef Pee Pee who (as his name implies) is a chef.