// Mummies can't quaff and don't care
    if (you.species == SP_MUMMY)
	return;
	

    switch (random2(8))

    int temp_rand = 8;
    if (you.is_undead)
	temp_rand--;
    switch (random2(temp_rand))

    
    if (you.species == SP_MUMMY)
        you.inv[3].quantity = 0; // remove potion

Your hear a croak.

You hear a croak.
%%%%
__GROWL
You hear an angry growl.

__HISS
You hear an angry hiss.
%%%%