Porta

Were you looking for Portal, the Forerunner complex?

A Porta opens for Master Chief.

A Porta is a sphincter-like orifice embedded into the floors and walls of Flood Hives that acts as the Flood analog to doorways. Portas were sighted in the Flood-infested High Charity and in the Halo 3 multi-player map Isolation. There are also seven portas on the level Cortana.

Trivia

• Portas may or may not be the doors on High Charity, covered in Flood biomass.
• Portas have at least two 7 references in them, one being that Portas are made up of 7 segments, and that there are 7 Portas on the level Cortana.
• The name, "porta", probably comes from the Greek word porta (πόρτα), which means door.
• Porta is also Latin for door
• On the Halo 3 multiplayer map Isolation there is one porta. Sliding down a hole on the top part of the map will lead you to slide down a tube. A porta will open, letting you into the Flood-infested cave.
• Portas make an appearance in Halo Wars on the flood barracks.
• There is a running joke among gamers that the porta's are the gravemind's intestinal openings, due to their sphincter-like appearance.