There was a running gag throughout the seasons of '3rd Rock From The Sun', in which the Solomons were terrorized by the sight of green Jell-O molds. They believed that Jell-O was an offshoot of a hostile, amorphous, carnivorous species from their home planet on the Cepheus-Draco border.
We've seen hostile amorphous species before in Toobworld, and they were green as well. We knew them as the Rutans, sworn enemies to the Sontaran race, and they had been locked in battle with the potato-headed clones for over 50,000 years. The Rutans were mentioned several times during the run of 'Doctor Who', but they only appeared once, in the 'Doctor Who' story "The Horror Of Fang Rock".
After watching the first half of 'The Sontaran Stratagem', NYMarkie of the Bit Torrent Rebel Alliance played for us the relevant clip from that Tom Baker episode, in which the Doctor had a sit-down detente with the Rutan on the stairs of the lighthouse. And we all agreed that it could be very likely that the Rutans were the aliens who terrified the Solomons.