create me a roblox script that allows me to block a player

Creating a script in Roblox to block a player typically involves manipulating `Player` objects and their interactions. However, while you can maintain a local list of blocked players in your game, you should note that Roblox does not allow modifying server-side code to block or restrict player interactions with other players.

Here's a simple example script that you could run on the **client-side** within a LocalScript, which allows a player to block another player by adding them to a "blocked" list and preventing any interactions or messages from them.

### LocalScript Example

Place this LocalScript in `StarterPlayerScripts`.

```lua
-- Block Player Script
local Players = game:GetService("Players")
local player = Players.LocalPlayer

-- A simple table to hold blocked players
local blockedPlayers = {}

-- Function to check if a player is blocked
local function isBlocked(targetPlayer)
    return blockedPlayers[targetPlayer.UserId] ~= nil
end

-- Function to block a player
local function blockPlayer(targetPlayer)
    if not isBlocked(targetPlayer) then
        blockedPlayers[targetPlayer.UserId] = true
        print(targetPlayer.Name .. " has been blocked.")
    else
        print(targetPlayer.Name .. " is already blocked.")
    end
end

-- Function to unblock a player
local function unblockPlayer(targetPlayer)
    if isBlocked(targetPlayer) then
        blockedPlayers[targetPlayer.UserId] = nil
        print(targetPlayer.Name .. " has been unblocked.")
    else
        print(targetPlayer.Name .. " is not blocked.")
    end
end

-- Example usage: Block player named "PlayerToBlock"
local targetPlayerName = "PlayerToBlock" -- Replace with the actual player's name you want to block
local targetPlayer = Players:FindFirstChild(targetPlayerName)

if targetPlayer then
    blockPlayer(targetPlayer)
else
    warn("Target player not found!")
end

-- Key press to unblock (for example by pressing 'U')
local UserInputService = game:GetService("UserInputService")

UserInputService.InputBegan:Connect(function(input, gameProcessed)
    if input.KeyCode == Enum.KeyCode.U and not gameProcessed then
        if targetPlayer then
            unblockPlayer(targetPlayer)
        end
    end
end)

-- Prevent interactions (You can expand this logic to include GUI messages).
Players.PlayerAdded:Connect(function(newPlayer)
    if isBlocked(newPlayer) then
        newPlayer.Chatted:Connect(function(message)
            print("Blocked message from " .. newPlayer.Name .. ": " .. message)
            -- Optionally, prevent GUI updates or ignore in other ways
        end)
    end
end)
```

### Explanation
1. **Blocked Players Table:** This script maintains a list of blocked players using their UserId.
2. **Blocking and Unblocking:** Functions are provided to block and unblock players.
3. **Input Handling:** It allows the player to unblock a player by pressing the 'U' key.
4. **Player Interactions:** It connects to the `PlayerAdded` event to ensure that any newly joined player is checked against the blocked list, preventing messages from unblocked players from being processed.

### Usage
- Replace `"PlayerToBlock"` with the actual player's name you wish to block.
- This script will only print a notification and ignore the message from blocked players in the chat. 

Note: This script is very basic and should be expanded with proper GUI elements and error handlers for production use. Also, be mindful of Roblox's community standards and guidelines when implementing any blocking features.