The man, known only as Vladmir, died within minutes of being bitten by the cobra - one of the most poisonous snakes in the world.
Anna, his girlfriend, was with the 21-year-old old at his flat in south-central Russia's Samara Oblast region, when the reptile attacked. She told police he was feeding the King Cobra when it suddenly struck him.
Its venom is considered to be among the most powerful of all poisonous snakes.
Vladimir collapsed and died in Anna's arms in a matter of minutes.
His terrified girlfriend immediately called an ambulance but there was nothing medics could do for him when they arrived.
Anna said:
"Vladimir was not afraid of his poisonous serpents and liked playing with them. His collection of snakes included a green mamba, a red spitting cobra and the king cobra, which killed him.
He had only had the snake for a short time."MirrorUk reports that Vladimir began collecting snakes only two years ago and his social media profile was filled with pictures of them.
It is unclear what will happen to the snakes, although Anna has said she does not want to take care of them.
But it is likely she will have no trouble selling off the king cobra which is highly prized among collectors around the world.
The snake - Ophiophagus hannah - is predominantly found in forests from India through to Southeast Asia.
This species is the world's longest venomous snake, with a length up to 18.8 feet.
