Stalker is the demonic "Game Over" grim reaper, protector of Jumanji and maybe the actual intelligence behind Jumanji. His name and destiny was never revealed in the show, but he was named in the 1997 Hasbro LCD game.
The Stalker is a towering, skeletonial bodied supernatural being with glaring red eyes, clad in purple robes and wearing black boots similar to Van Pelt and a large hat with a red plume, akin to the Walt Disney version of Captain Hook. He dwells within the fiery furnace core of Jumanji, venturing outside on a Mine Cart. Stalker keeps track of what players are doing through cameras and microphones disguised as flowers, (not unlike how Ibsen collects his own data) appearing whenever Jumanji is threatened or the game rules have been drastically changed.
When Judy and Peter return to the real world, Alan grabs onto them to return with them. Before Jumanji pulls him back in, he steals the dice so that Peter and Judy can no longer play or be caught in danger. Alan discovers inside Jumanji that the dice (glowing red) scared Van Pelt and the animals away, realising the dice repel any danger Jumanji unleashes on him. This doesn't last, as he falls down into the inner mechanical bowels of Jumanji.
There he's confronted by the Stalker of Jumanji who wants to apprehend the terrified Alan and retrieve the dice, restoring balance to the jungle of the game. He chases Alan across the cogs and gears beneath the surface. Near a lava river, Alan runs into the kids again, who must flow down the lava to solve the clue and take the dice back home. Nearly killed by the Stalker, they crush him under the cogs, but he disappeared without a trace before he got smashed, left nothing, but his black cloak behind. On the boat ride down the river, they ride round the bend and the kids return home with the dice while Alan sails out into the jungle vowing that together they'll beat the game. But unbeknownst to them, Stalker survives and plots for revenge, but is satisfied that the dice have been returned to the outside world so that people can still play the game.
When Judy and Peter enter Jumanji for Alan's birthday, he is bitten by a centipede that passed green venom through his veins toward to his heart. if it does, he'll die. Peter vows in anger that he'll destroy the game if Alan dies. Without noticing, Stalker overhears with a microphone disguised as a flower plant, and takes immediate action to kill the children and Alan in order to protect Jumanji, enlisting Slick, Van Pelt, and Ibsen to do the task. But the villains fail their task when the kids elude them and Tribal Bob and the Manjis carrying off the villains to help the kids, requiring Stalker to do his mission himself. As Peter fends him off, Alan is closer to death when the venom reaches his heart and Judy has the Mosquito suck out the venom. Fully healed, Alan then shoves Stalker off a cliff and down to the bottom of the waterfall, saving Peter. After Judy and Peter leave, Stalker emerges from the water and vows for more revenge someday.
In the 1997 Hasbro LCD Game, the Stalker appears on each level after completing the maze and solving the puzzle, where the player must defeat the Stalker before they can be awarded a letter to spell Jumanji. The Stalker's die will be shown in the middle of the screen. Press ROLL to roll Peter's, Judy's, Alan's and the Stalker's dice. If one of their dice matches the Stalker's, press their respective HOLD button and continue rolling the other two dice. If all three dice match with the Stalker's before time runs out, the player wins. If the three dice do not match in the allotted time then they will lose a life and must try again. Also, any weapons accumulated in the maze can be used as extra lives.
- Terrifying aura: The Stalker is a terrifying supernatural being that evokes absolute fear in the presence of everything around him, including Professor J.S. Heinrich Ibsen, J.H. "Trader" Slick, Manjis and even the dangerous game hunter Van Pelt.
- Strength: The Stalker is incredibly strong as he was able to pick up a Jaguar that Van Pelt was hunting, and cast it aside with ease. He was able to lift a piston even when it was deactivated, and managed to hold it off long enough before being crushed by the emergency shut down lever. When Judy pulled at the Stalker's robes to stop him from pursuing her brother, he merely slapped her aside and sent her flying into a wall.
- Disintegration: When Peter left his shoe in the Stalker's grasp, he melted it in his hand, indicating his touch is very lethal.
- Invincibility: Despite apparently being crushed to death by a piston and falling off a waterfall, the Stalker has always emerged unchanged, hinting he is unkillable as the death avatar of Jumanji.
- Dice glare immunity: When the game's dice are taken into Jumanji, they glow red and can scare off any danger. Although when Alan tried to repel Stalker this way, he merely laughed at the futility and unfolded his boney hand out asking for the dice instead.
- Gliding: Alan had a difficult time running and jumping between engines in the Jumanji backstage level; but the Stalker simply glided after him with great speed.
- Despite promising to himself that he will return to take revenge on Alan, Judy and Peter someday, the Stalker never did come back to bother the trio again. In "Armageddon", even when Jumanji was facing certain annihilation and the trio entering the "Backstage" of Jumanji through the Bog of despair like they did in No Dice, Stalker does not reappear.