It's sad that this thing is most remembered for introducing cute Yeti as a recurring villain, which is not a brilliant way to portray an extra dimensional being of unspeakable power. This things solution to the ending of its own universe was to causally jump two universes in the space of a second so that it could take the scenic route through another collapsing universe to get into our. Which at the time was going through the Big Bang. No big deal. And then itll go on to possess any living thing. Then itll become even stronger because of the fact that it completely absorbs their soul. As a snack. The Daleks also tried absorbing the minds of people in the 1960s and ended up creating the Robomen. And they were more of an embarrassing creation than the cuddly Yeti. Yup, the Great Intelligence wins this round.