It's a rope tornado
https://www.spc.noaa.gov/faq/tornado/el_reno.htm
Tornadoes often assume a ropy, sinuous shape in their final minutes; but they can remain narrow like this during their entire life cycles. Although "rope" tornadoes may look weaker than much larger ones, some get more intense as they narrow and tighten (the ice skater effect). With tornadoes, size does not necessarily indicate strength!