They make draft beer dispensers where there’s a little magnet in the bottom of a plastic cup. The bartender puts the cup on a nozzle and it feels it up with beer from the bottom.

Normally the hole with the magnet thing is on then bottom and a different color and people get curious and poke it causing beer to spill all over the bar and usually the person drinking it.

A local bar had one for a while - it was a neat novelty but they finally took it out and put in a regular draft system