Like large Millipede having gills and many legs, a head and tail seem to be present.
No interactions present.
Certainly not a terrestrial environment, crinoid is likely.
All given ID's are subject to error/ommissions. Please seek independent verification before acting on ANY advice given. BE SAFE =)
P.s. Crinoids are animals lol ;-)
Lat/Lng: 54.547, -0.7682
OS grid ref: NZ797175
On beach next to recent landslip