Format:
cast 'detect invisibility'              cost: 12 mana
cast 'invisibility' <target>            cost: 45 mana

Invisibility and detection thereof are fairly high level spells on this mud.
You should not need either for some time. Invisibility is castable on others,
and on objects. Detect invisibility, however, can only be cast on yourself.
Invisibility will not fade when attacking, and can be an advantage when
fighting creatures without the ability to see you.