Evard's black tentacles

Evard’s black tentacles was a conjuration spell that filled a area with black restraining tentacles.

Effect
For up to a minute the tentacles would try and restrain any thing that entered or stayed in the area and cause blunt damage. The area that was covered by the tentacles (20 foot square) would be difficult too traverse.

Components
Vocal and somatic components where needed as well as a tentacle from a Giant Squid or octopus.