Dark matter magnetic devices

One day we could have devices that can magnetically collect and hold onto dark matter. With enough dark matter the devices can pull on weight and weigh more when in use. Like a 1 meter square plate could weigh 1 ton in dark matter energy. Dark matter or other energies that can add up weight.

This can be used for space travel where we need more weight when stopped or something. Or for weight elevators that go up and down there’s weight on the other side with a pulley.

There can also be dark matter or dark energy that can work like anti-mass, making things weigh less or float above it.