viscous
ˈvɪskəs/
adjective
having a thick, sticky consistency between solid and liquid; having a high viscosity.
"viscous lava"
synonyms:
sticky, gummy, glue-like, gluey, adhesive, tacky, adhering, adherent, sticking, clinging, treacly, syrupy;
glutinous, gelatinous, thick, viscid, pasty, mucous, mucoid, mucilaginous, jelly-like, slimy;
informalgooey, gunky, gloopy, cloggy, icky;
informalgloppy;
rareviscoid
"pools of viscous liquid had started to spread across the floor"