Grasping Roots is a special ability unique to shambling mangroves which causes the network of roots running beneath the earth to rise. These roots apply a 3 aut movement delay penalty and -33% EV reduction to any hostile creature standing on solid ground or shallow water within sight of the mangrove. Creatures above lava and deep water are unaffected. Flying creatures are also unimpeded, but the roots have a high chance of rising up and pulling them back to the ground.
The following enemies cast Grasping Roots:
In 0.23, this spell will be reworked to instead constrict and deal damage the target in a manner similar to the player spell Borgnjor's Vile Clutch, but affecting a single tile. This will hold the target in place and reduce EV until they escape or until the roots release them, but will not then subsequently reduce movement delay or EV, and will not prevent flight.
Grasping Roots was added in 0.14.