In the "Monstertainment" episode, where the crew's been sucked into a Frankenstein film by a ghost, Scooby plays Dr Frankenstein who brings a monster to life. It chases him and Shaggy, but later gets trapped under a collapsed roof. Shaggy's instinct is to run, but when the monster starts crying Scooby puts aside his fear and helps out the monster. This is what makes Scooby a Lovable Coward and not a Dirty Coward.
This act of kindness has the monster calling him "Mommy" for the rest of the episode (which isn't wrong, since Scooby is playing its father figure). The monster helps out by attacking the ghost, and at the end is able to escape the film and stay with Scooby, who's actually pleased with this development. It's actually really sweet that Scooby gets a son, and even though he's a monster, he doesn't mind.