. And I believe Rock to Mud followed by Mud to Rock was the common tactic.
That's two 6th level spells, only useable vs non-flying/levitating foes at range, who are standing on unworked stone. In the hands of any decent DM it's a moderately effective but highly limited tactic.
I mean, did you guys even notice that 1e Harm is also a 6th level spell, no save, that reduces target to 1d4 hp?