Unopened Special Rooms will cycle between three different types of rooms, indicated by the red door frame. Upon entering or unlocking the red door, the room will be permanently transformed into the type of room that was last displayed.
The choices that can appear from Too Many Options do not necessarily include the type of room it initially generated as.
The original room's door will determine the cost for its entry, even if a room that normally has a different entry method replaces it — for example, a room that was originally a Curse Room having spikes in the door frame which will hurt Isaac, or a Bedroom having wooden boards over the door that require two Bombs to open.
Likewise, the door frame of the room will change to the new type after it has been entered. For example, a door of a Curse Room that changes to lead into a Treasure Room will cause the spikes to disappear from the door frame after it is entered — and vice-versa, where entering a Treasure Room door that has changed to lead into a Curse Room will have the door change to have spikes, requiring Isaac to take damage to leave.
Room Choices
The different possible choices of room that Too Many Options can cycle through are as follows:
Opening up the wall of a Special Room that is adjacent to Secret Room will have the room continue to cycle through its options if the room has not been entered yet. However, the options are not visible from inside the Secret Room, as there is no door frame.
If Isaac has any sort of effect that teleports them to a specific type of Special Room on the floor, and the floor has no rooms of the correct type due to the rooms being rerolled, then the teleportation effect will fail and take Isaac to a random room.
However, teleportation effects to specific Special Rooms will still work as intended if the original room has not yet been rerolled — this will cause the room to revert into its original state, even if it wasn't one of the options on the door frame created by Too Many Options (For example, using XVII - The Stars will teleport Isaac to where the Treasure Room would have generated, and the layout will always be the layout of the original Treasure Room).
Having additional copies of Too Many Options adds an additional choice to each door for each copy. The time it takes to cycle through all of the door's choices is unaffected, meaning each choice has a lower time frame and thus making it more difficult to choose a specific room.
Angel Room, 
Arcade, 
Bedroom, 
Curse Room, 
Devil Room, 
Dice Room, 
Library, 
Planetarium, 
Sacrifice Room, 
Shop, 
Treasure Room, and 
Vault. All other types of rooms are ignored.
Bombs to open.
Secret Room will have the room continue to cycle through its options if the room has not been entered yet. However, the options are not visible from inside the Secret Room, as there is no door frame.
XVII - The Stars will teleport Isaac to where the Treasure Room would have generated, and the layout will always be the layout of the original Treasure Room).
