White Sludge of Goonstefer

Send out a ball of white that, upon landing, can either fully liquify to allow it to expand up to 30 ft. or solidify to create a barrier with an armor class of 8 plus your spell modifier.

If a creature walks into the sludge, regardless of liquidity or solidity, they are slowed by 10 ft. and poisoned for 1d4 plus half your spell modifier. The damage retains until the creature is downed or moves out of the sludge. If a creature is downed in the sludge without being removed from it, all saving throws are made with disadvantage.