Recently, I was running a game where the party was flying in an urban environment to face off against a wizard. They were all bunched together next to a building about 20' up to avoid attacks from the wizard's constructs but were right next to a wall.
I decided to open with Evard's Black Tentacles using the wall behind them as an anchor point. The party balked saying that the Black Tentacles only went up. This didn't surprise me considering my action would have wrecked the party but I was left wondering later if I got situationally convinced.
3D in D&D has never been my strong suit but the only clue in the spell itself seems to be the word "underfoot". One could argue either way that if you're "standing" on a wall (flying, perfect) the wall is "under" your feet. This is only added to by the confusion that there's no facing in D&D, so flying everywhere could be under your feet=)
Thus in my logic, I went with the surface, which a wall seems no worse than a floor.
Is there another reference anywhere that might clear this up?
Best Answer
I was unable to find any reference beyond the RAW description of the spell, but I think it's reasonable to assume it can be cast on a wall. My reasons are as follows:
RAW Explanations:
Meta Explanation:
3.5 is hardly known for restricting what players can do. Given that Evard's is on the lower end of "optimized caster options", a fair DM would be hard-pressed to limit it in this capacity. Plus, consider it from a caster's point of view. He or she is magically assembling and maintaining these tentacles from the fabric of creation - does it really seem likely that orientation is the core issue?