Corrupted Magic

As you outstretched your arm and open your hand a beam of purple black light shoots out of it. From within the beam tentacles shoot out and whip about around the beam uncontrollably and destroy everything near them. Every one with in 20 ft of the spell has to make a dexterity save of 10 of higher. If failed they take 1d12+5 I’d they succeed the save they take 1d6

everything fought within the beam is instantly destroyed and anything caught by the tentacles are thrown around.