I think 3 or 4 runoffs.
https://rrhelections.com/index.php/2018/11/26/mississippi-senate-special-runoff-preview/
two races D v D races
There are also two legislative specials this Tuesday in Mississippi, both D-on-D runoffs for deep-blue seats. MS-LD-31 is a rural D+20 seat in the Delta region around Indianola. 2011 candidate Otis Anthony (D) led businesswoman Barbara-Rose Brooks (D) 22-19 in the eight-candidate first round; there is no clear favorite in the runoff. MS-LD-85 is a rural D+19 seat around Port Gibson, south of Vicksburg. Two Dems are facing off: attorney Jefferey Harness (D), who ran for this seat in 2011 and the State Senate in 2015, led retired teacher Joann Collins-Smith (D) 35-28 three weeks ago. Harness seems a slight favorite but an upset is possible.