Actually, I think the best way would be to make little note cards for each save effect/after effect.
I'd use postit notes, write up a whole bunch ahead of time,a nd then hand them out as it came down the pike. For every note someone had, they would need to roll a save, and follow the failed/after effect on the card.
Considering the number of saves PCs are making, I think the Ultimate beholder's go-to starting ray would be the Cold Ray; a flat -2 to saves is pretty vicious.
In fact, Cold ray + Unraveling ray is rather nasty.