Spriteflags

spriteflags <value>

Sets special flags for sprites. The values are:

1 - Generates a shadow. See spriteshadow.
2 - Turns palette 6 whenever night vision goggles are used. See spritenvg.
4 - The sprite's shade is unaffected by the shade of its sector.
8 - Is a projectile.
16 - Prevents teleporting. The sprite is not entered into the decal deletion queue.
32 - Is an enemy. See useractor.

It is a bitfield, so add together the values you want and then use spriteflags with the sum.