Sussex's Steve Magoffin took 8-20, the best bowling performance of his career, as Somerset were routed for just 76 on the opening day of the County Championship game at Horsham.
By the close of a first day in which 19 wickets fell, Magoffin was back in the middle and undefeated on 21 as Sussex closed on 298-9, a lead of 222.
The 33-year-old Australian took five wickets in 13 balls at one stage as Somerset, who won the toss, were bowled out in 23.4 overs.
Magoffin bowled 11 overs unchanged to produce the best performance by a Sussex bowler since Mushtaq Ahmed took 9-48 when the county clinched the Championship title against Nottinghamshire at Trent Bridge in 2006.
He started by bowling Arul Suppiah through the gate then a touch of inswing proved too much for Alviro Petersen, but the major damage was done after James Hildreth was caught low down at slip in the 12th over.
From 42-3 Somerset subsided to 43-7, with Magoffin taking three wickets in four balls in the 14th over.
Marcus Trescothick (20) was caught behind playing away from his body before Peter Trego and Alfonso Thomas fell in successive deliveries.
Somerset's last three wickets put on 33 to avoid total ignominy but there was no stopping Magoffin.
After Jack Leach was caught behind, the Queenslander bowled top scorer Jos Buttler for 22 to pick up his eighth wicket and record the best bowling performance at Horsham since Northamptonshire's Vince Broderick took 9-35 in 1948.
Chris Jordan took the other two wickets and Sussex openers Chris Nash and Luke Wells were soon putting conditions into perspective with a stand of 83.
Thomas dragged Somerset back into contention when Nash, captaining Sussex on his home ground in the absence of Ed Joyce, played on before Joe Gatting edged his second ball to second slip.
A typically fiery burst from Steve Kirby was rewarded with the wicket of Wells while Mike Yardy, who hit three successive balls from Kirby to the boundary, squandered a good start when he was bowled by Peter Trego at the start of a new spell.
But Sussex regained control in a fifth wicket stand of 85 between Rory Hamilton-Brown and Matt Machan before the latter was run out by Leach's direct hit from midwicket.
Somerset fought back after tea by taking five wickets, including Hamilton-Brown -whose 77 included 11 fours and two sixes and was his highest score since returning to the county before he became one of four victims for Thomas.
Despite the clatter of wickets, ECB pitch inspector David Capel said he was perfectly happy with the surface.