Elliot Decker is the arch-nemesis of Milo Murphy. He is a volunteer school crossing guard who spies on Milo.

He does not take kindly to Milo, mainly because the misfortunes that regularly happen around him. Elliot is one of the many people who are aware of Milo's reputation of extreme misfortune and finding ways to overcome it. However, unlike those who are civil towards Milo, Elliot is openly delusional and hostile towards Milo. He sees him as a danger to Swamp City. He is also shown to be arrogant, always stating that it is his duty as an enforcer for public safety to protect Swamp City from Milo, despite that he is just a volunteer crossing guard.
Elliot is very obsessed in watching what Milo gets up to, even putting Milo's name on the back side of his stop sign to mean business. He ensures everyone and anyone that he will always have his eyes on Milo no matter what. He is voiced by Christian Slater.