There are three different levels in Mt. Moon, populated by four types of Pokémon and multiple trainers. Also along the way, you'll notice that the criminal gang Team Rocket is carrying out an operation in Mt. Moon, and it's up to you to blow their operation wide open!
There's a Rare Candy within Mt. Moon, but save it for now. Your Pokemon level up too fast right now to justify using a Rare Candy. In addition, Mt. Moon is where you will find your first Evolutionary Stones. The Moon Stones you find here can be used to evolve Nidorino, Nidorina, Jigglypuff, or Clefairy. If you wish to use it on Nidorino/a, you should wait to do so at Level 22, and only at 22, to gain access to great moves for both.
Moonstone (BF2: hidden in rock before you choose a fossil)
Revive (BF2: last ladder)
Helix Fossil (BF2, can choose only 1 fossil), can be resurrected into Omanyte.
Dome Fossil (BF2, can choose only 1 fossil), can be resurrected into Kabuto
Antidote (BF2)
New Pokémon
#41 Zubat
#74 Geodude
Zubat The most common Pokémon among caves in all the Pokémon Core games. At this part of the game you can only evolve it into Golbat. In order to evolve it further into Crobat, you will need to beat the Elite Four and to raise Golbat's happiness to the maximum. Crobat, however, is an excellent Pokémon which has decent Attack and magnificent Speed. You can catch Zubat later because Golbat doesn't do very well on the Elite Four.
Geodude The first Rock-type Pokémon in this game. It has powerful attacks early on and is easy to train. However, it can't stand Water- nor Grass-type attacks so be cautious when using it. It evolves into Graveler by leveling up and then into Golem by trading. Golem, however, is inferior to Rhydon (which is also a Rock/Ground-type Pokémon) statwise and Rhydon can be obtained easier since Rhyhorn doesn't need to be traded to evolve.
#46 Paras
#35 Clefairy
Paras A weak Bug/Grass-type Pokémon which can be easily found in Basement Floor 1. It evolves into Parasect. It has numerous weaknesses and its stats are quite poor (especially Speed), so using it isn't recommendable.
A caught Paras has a chance of holding a Tiny Mushroom or a Big Mushroom. These items, worthless now, have a purpose much later in the game, serving as a currency for an unique Move Tutor that can reteach a Pokemon its early moves.
Clefairy Clefairy the Moon Pokémon. It has some decent attacks and some very useful egg moves, though its Attack isn't that high. It is a bit difficult to find, but it can be bought at Celadon City afterwards.
It evolves into Clefable by using the Moon Stone. Clefable may be worth a second look, as it is capable of learning the wonderful move Soft-Boiled from a Move Tutor, a feat otherwise only available to Chansey.
Zubat
Geodude
Paras
Clefairy
Weedle 11
Kakuna 11
132
Iris
Magnemite 11
Voltorb 11
Caterpie 10
Metapod 10
Oddish 11
Bellsprout 11
Josh
Rattata 10
Marcos
Onix 10
Grunt
Sandshrew 11
Ekans 11
Grimer 12
Koffing 12