Um.... so in Link and Zelda: Panoply of Calatia, I set Link->Action = LA_DROWNING whenever Link steps on a CT_SCRIPT2 combo (a pit), which would make him invisible, but only until the drowning action ended, and then would spawn him properly just as if he fell into walkable water. I also had him do this if he went above certain ComboDs in sideview screens (for lava combos). It worked fine in 2.50.2.... I haven't tried it in 2.50.3 or Zoria's betas yet, though.