Snoops' personality is that of the typical minion; timid, cowardly, and basically a yes-man to Medusa. He attempts to be a serious bad guy, but fails miserably, as he doesn't always handle Penny's strong personality. He's also terrified of Brutus and Nero.
When hearing Mr. Snoops on the other end of the phone, Medusa is at first delighted, thinking that he has "found the diamond," but soon becomes furious when Snoops tells her that Penny has been sending messages in bottles. She angrily tells him that she will take the next flight to Devil's Bayou and starts packing immediately.
Mr. Snoops is next seen in a riverboat in Devil's Bayou with Medusa and her pet crocodiles Nero and Brutus keeping Penny captive. However, Penny manages to escape. Upon discovering this, Medusa sends Nero and Brutus to bring the girl back, and orders Snoops to send up flares to light up the swamp while she looks for Penny in her swamp mobile. The fireworks surprise Orville, who is taking Bernard and Miss Bianca to the swamp, and set his tail on fire. The two mice bailout, but all three land safely. They meet Ellie Mae and Luke, who tells them that they want to run Medusa out of the swamp. Nero and Brutus find Penny and take her (and her Teddy) to the riverboat where Mr. Snoops is waiting. "Bring her right on in, boys! Hehe, c'mon!" he calls to the two as they carry Penny upside down by her pants, then attempts to tell Penny off and sends her up to her room. Snoops send up more fireworks to tell Medusa that Penny is back in the riverboat, and Medusa returns, yelling at Snoops for letting Penny escape in the first place.
Meanwhile, the mice sneak onto the boat (having been taken there by Evinrude and discover that she is after the Devil's Eye, a huge diamond and that Penny is the only one small enough to crawl down into the Black Hole, a pirate's cave where the diamond is hidden. Medusa and Snoops leave the room, but Nero and Brutus smell Miss Bianca's perfume, and a chase ensues. Medusa returns to shut her pets up, but screams when she sees the mice, and calls Snoops to help. Snoops attack the mice with a broom, and Brutus and Nero chase them, but when Medusa pulls out a huge gun and tries to shoot the mice, everyone runs for cover. Bernard and Bianca manage to escape with their lives. Medusa decides that she will send Penny down to the cave until she retrieves the Devil's Eye, whether or not the tide comes in. Meanwhile, Bernard and Miss Bianca meet Penny and the three plot Penny's escape and Medusa's defeat.
Medusa and Snoops take Penny to the entrance to the pirate cave. Snatching Teddy away, Medusa orders Penny to get the Devil's Eye under the threat of never seeing her teddy bear again. The two mice hide in Penny's pocket and when Penny gets into the cave, they help her to find the diamond. It is discovered inside a skull, which the mice pry open, and Penny recovers the diamond just as the tide comes in. Snoops pull Penny out of the cave and Medusa snatches the Devil's Eye from her. At one point, Snoops drops Penny from the bucket as he attempts a better look at the diamond. Snoops demand an equal share after Medusa claims the diamond is now all hers and nobody else, and they return to the boat, arguing all the way. Penny is carried upside down after the two. Meanwhile, Evinrude reaches the swamp gang, giving them the signal to 'charge'; they all make for the riverboat, where Medusa is making her escape with the diamond, leaving Snoops and Penny on the ship, having sewn it inside Penny's teddy bear and holding Penny and Snoops at bay with her shotgun. Bernard and Miss Bianca trip Medusa up; she drops the diamond, and she and Snoops fight over it. The swamp gang attacks Medusa; she shoots at them, but Ellie Mae jumps on her head and hits her with a rolling pin. The swamp gang also manages to destroy Medusa's gun, confuse her by setting off Snoops' fireworks and trap Nero and Brutus in a cage. Penny, Bernard, Bianca, and the swamp gang escape on Medusa's swamp mobile, but she grabs onto it and drags along behind until a sharp turn causes her to lose her grip and slam into a large smokestack from the riverboat. She is left clinging onto the stack as Nero and Brutus, now free from the cage, snap at her. Snoops is last seen on a piece of wood (used as a raft), with his torn clothes, he points at her and laughs at her before rowing away, leaving her to fend for herself. It is unknown if Snoops managed to escape from Devil's Bayou and even if he did, he was possibly detained by the police, as Penny could have told her adoptive parents about his involvement in her kidnapping.
Mr. Snoops is seen far from a robot who is clapping his hands.
- Elmo St. Peters from The Brave Little Toaster seems to (rather strongly) resemble him in both looks and voice.
- Joe Flynn, the voice of Mr. Snoops, died on July 19, 1974, from drowning shortly after completing this role, making this his last role and a posthumous one, too.
- Mr. Snoops was modeled off of John Culhane; "Mr. Snoops" was the animators' nickname for the nosy Culhane, who would often come into the studio to inspect the animators on their work. As a practical joke of sorts, the animators would trick Culhane into doing poses for them so he provided unwitting live action reference.