Snake

The Snakes encountered in the Resident Evil franchise are animals which mainly serve as jump-scares and traps. They first appeared in this form in Resident Evil 4, where they relaxed in wooden crates which Leon S. Kennedy would usually find useful items such as ammunition or herbs. When the boxes were destroyed, they would quickly lunge at Leon and if he wasn't fast enough with his weapon, they would get a quick hit and escape. They subsequently appeared in Resident Evil 5, Resident Evil 6, Resident Evil: The Umbrella Chronicles and Resident Evil: Revelations 2 in a similar fashion.

The Snakes in Resident Evil 4 May have been infected with a Plaga parasite, a kind of organism which can change physical and mental characteristics of its host, because when they are killed they dissolve in a similar manner to Ganado when they are killed. However, they don't possess any of the other characteristics of a Plaga infection such as increased strength and other physical mutations. Also in most appearances, they drop Eggs as items when killed. In all other appearances the Snakes seem to be un-infected.

There have also been occasions where snakes have been used as the base for virus infections by Umbrella. In all cases they have grown dramatically in size, speed, intelligence and aggression. The most infamous of these was Yawn, an adder which grew to around 40ft long (an average un-infected adder usually won't be longer than 3ft long).

In the original Resident Evil and Resident Evil: Director's Cut, Snakes appeared as normal enemies albeit rarely. They were dark in colour and simply slithered across the ground. They earned a reputation of being relatively harmless as they were easy to avoid and they only had one attack.