An ERC20 token that can only be transferred to the address which created it

ERC20Unidirectional.sol

pragma solidity ^0.4.24;

import "./ERC20.sol";

/**
* @title One-way Fungible Token
*/
contract ERC20Unidirectional is ERC20 {
    address private _parent;

    constructor(address parent) {
        _parent = parent;
    }

    function transfer(address to, uint256 value) public returns (bool) {
        require(to == _parent, "must transfer to parent");

        _transfer(msg.sender, to, value);
        return true;
    }
}