Unfathomed
Not completely explored
Sluice
Sliding gate that controls waterflow
Tentacle
Slender limb
Corrugated
Creased, folded, fluted
Lurching
Slipping, weaving, reeling
Oblique
Tilting, diagonal
Annihilate
Root out, obliterate, wipe out
Perpendicular
Extremely steep, upright
Dereliction
Neglect, ruin