Space yetis (also "dayglo psychlos") are fat EBM fans who show up at Goth clubs dressed in fluorescent vinyl, yarn hair, goggles and Transmuters weighing over 250 lbs. One of the many unfortunate side effects of sellout Goth club DJs no longer playing Gothic music, opting instead to ear-rape club patrons with Industrial, metal and EBM music. They look like someone attacked a Psychlo from Battlefield Earth with 20 gallons of glow in the dark paint and mohair. Their giant boot treads and tardtastic clothing/yarn hair make them look like sasquatches from outer space. Hence the name "space yetis".
I use to go out to Goth clubs. But no self-respecting Goth has been to a club since 1999. Now all you find there are metalhead-wannabe-goths, fang-tards, rivetheads and space yetis dancing to music that sounds like a malfunctioning alarm clock.