It'll probably be better for you to get a chocobo. That way you can zip through the marshes with the Chocobo. It's the only way to avoid being attacked by the Midgar Zolom.
The Marshes is both an area on the world map and a one-time visit field location in Final Fantasy VII. The marshes are a portion of area on the world map separating the majority of the Grasslands Area from the entrance to the Mythril Mine. The marshes are inhabited by the Midgar Zolom, a giant snake that has prevented workers at the mine from mining.
The Midgar Zolom appears as a long shadow moving through the swamp. It travels in random direction until the player moves close enough when it moves towards the player. The player can cross the marshes either on foot or on Chocobo by obtaining the Chocobo Lure Materia from the Chocobo Farm to help catch one. On a Chocobo it is easier to cross the marshes without being caught by the Midgar Zolom, since it can outrun the snake.
Once the player has crossed the marshes for the first time, they enter a single screen field location titled "Marshes". When entering the camera only shows the ground of the marsh, but as the party runs up the camera pans up to show an impaled Midgar Zolom, which the party assumes was defeated by Sephiroth.
After the initial panning of the screen, there are no further scenes with dialogue. Cloud can talk to the other members of the party, who will each offer one line of text. Other than talking to other party members, the only other thing the player can do is exit the screen. Afterward the player can never return to this field location.
|Aeris||"Our enemy is someone that|
could do this?"
|Barret||"This Sephiroth guy's|
pretty strong‚ I'd say."
|Red XIII||"It's a power that we should respect..."|
It is not possible to have Yuffie in the party at this point, since the first forests she can be fought at are beyond the Mythril Mine in the Junon Area. The player cannot see her dialogue in a normal playthrough unless they perform the skipping the Midgar Zolom scene glitch and return with Yuffie in the party to watch it.
In this area in the field, the "Trail of Blood" (血の跡, Chi no Ato?) theme plays.