Clear DDM...

[Ogrork the Mighty]

Just read that clear D&D minis are on the drawing boards. Cool! I think they should make a humanoid-shaped creature out of clear plastic that can be used for invisible characters...

 

[The Shaman]

Air, fire, and water elementals all look good in various shades of clear(-ish) plastic.

Spectre could be another option.

 

[mearls]

Gelatinous Cuuuuube!

 

[Ankh-Morpork Guard]

Gelatinous Cuuuuube!

My thoughts EXACTLY

 

[Nightfall]

Ghosts.

 

[Lonely Tylenol]

Cuuuuube ...the DIY version.

 

[DaveMage]

Invisible stalker!