The game you’re probably thinking of is Mystery Flesh Pit National Park on Roblox, a horror game based on the “flesh pit” concept and commonly described that way in Roblox fandom pages and videos. The clue about a “big red meat cave” matches that vibe pretty closely.

What it is

It’s a creepy exploration/horror Roblox experience set inside a giant organic underground structure, with players exploring something that looks like a living, fleshy cave or pit. The Roblox wiki for the game describes it as Mystery Flesh Pit National Park.

Why people call it that

Online discussions and videos often use words like “meat,” “flesh,” or “living organism” because the whole map has that gross, biological look. One Roblox video even frames it as “The Roblox FLESH National Park,” which fits the “big red meat cave” description.

If you meant a different game

A few other Roblox games have caves or red cavern areas, but the most obvious match for “big red meat cave” is still Mystery Flesh Pit National Park. Another flesh-themed Roblox project also exists under names like “Meat Canyon Mystery Flesh Pit National Park,” which may be part of why the name gets mixed around.

TL;DR: it’s most likely Mystery Flesh Pit National Park on Roblox.