Simply using Great Aether on three pairs of Ice Climbers.
Since I was too lazy at the time to get four controllers plugged in, I used three cpus to get the shot, and it was a little tricky (with them often getting the Smash Ball and not all six being in range). But I was eventually able to land the Great Aether on all six of them.
Note: Credit to
for suggesting the title.
Super Smash Bros. ~ Nintendo/HAL Laboratories
Fire Emblem ~ Nintendo
Ice Climber ~ Nintendo