no_bump

[Sophia]

Uff, I'd seen a no_bump flag on the DSB monsters and had assumed it was set to false for the ghost. Wrong!...

no_bump means the party won't make the "OOF!" noise and take damage if you hit it. Whether or not whatever it is actually blocks the party is handled by the collision function. These can be conditional, so different things will happen depending on what is colliding with what. This is how fireballs pass through ghosts but des-ews hit them, for example.

[ian_scho]

Ah hah. I see the col=nonmat_col attribute for the ghost now... Not setting it at all (or false or nil) would make the creature just like a puddle, say? You'd walk through it and can't hit it.

[Sophia]

Yes, exactly. And col=true would make everything hit it.