you can set texture flags in order to 'mark' a texture - for example if you want to make a lava pit in your level, you create a block with lava texture applied, and set it's Flag1 for example. Then in the player's movement code after the trace with 'scan_texture' flag you check if the ground texture has Flag1 checked, if so - subtract players health, or do something similar.
You can change x\y scale of texture in the surface tab(individually per surface), or if you want to do this to an object with lots of surfaces, change x\y scale of texture before applying it to object.