In the tunnels under the Spencer Mansion, two booby traps set off boulders that roll down the hallways. The player must run away from these boulder to avoid being crushed and to reveal a door. The boulder trap is still present in Director Cut and the Remake.
Resident Evil 4
A few boulders appear in Resident Evil 4. The first one is a booby trap set by the village ganados in attempt to crush Leon. In order to escape it, a quick time event must be played where the player has to rapidly press the run button or shake the Wii remote and then press the dodge buttons. The ganados do this type of trap again along the path to the swamp.
Two other boulders can be found in the right path after the cabin fight that features the optional second El Gigante fight. These boulders are both an aid and a hazard to Leon. They can be shot down on top of the El Gigante to injure it. Leon can also accidentally crush himself or Ashley with these rocks if shot down while standing in the wrong place.
On the island, the militia set one up to fall on Leon. The player only needs to dodge this one.
A last interactive boulder can be blown up by setting off the red barrels next to it opening up the path to the Golden Lynx.
Resident Evil 5
The only notable boulder that appears in Resident Evil 5 is during the ending fight with Wesker. However the boulder's role here changes, when Sheva reaches the end of the volcano path, Chris finds he has to create a stepping stone by moving a boulder at the edge of his path. Hyped on adrenaline, Chris struggles to push and manages to punch the boulder into the lava to save Sheva.
In game, the moving the boulder sequence in done through a quick time event. On Xbox 360 the player must rapidly push X, then circle the thumbstick, B, X, A, then push X and A to complete the sequence. On PlayStation 3 the buttons are square, analog stick, O, square, X, and then square and X.
Resident Evil 6
In Chapter 3 of Leon's Campaign in the catacombs, there are two instances where Leon and Helena must push a boulder off a ledge to progress further.