Enemy skills are learned from enemies (obviously). They are some of the most useful spells in the game. Most of them either have new effects, stronger effects, or cheaper effects than the normal spells (if you can find them). These are in the same order as they are in the Enemy Skill materia. You get the first one in Hojo's machine after fighting his "sample." The second is in one of the Shinra's Junon harbor shops. The third is in the City of Ancients. That should be all you need, but their is a fourth in the Chocobo Sage's house (talk to the chocobo).

Frog Song- This enemy skill isn't that good. It hits one enemy with frog and sleep. Get this from any of the "frog" enemies (temple of ancients, or forests near Cosmo Canyon).

Level 4 Suicide- This isn't that good either. It hits all enemies with a level 4, 8, etc. with damage and mini. Get it from the Mus (the creatures in the ground) near the Chocobo Ranch.

Magic Hammer- An extremely useful enemy skill. This drains 100 MP out of an enemy. Get it from the Razorweed on Yuffie's continent.

White Wind- Another very useful enemy skill that heals all of your characters an amount equal to the current HP of the caster. Get it by manipulating Zemzelzats (the giant birds) near Fort Condor.

Big Guard- Casts Wall and Haste on all characters. EXTREMELY useful against bosses. Get this by manipulating the Beach Plugs on the beaches near Costa del Sol.

Angel Whisper- Casts Life2 (if the character is dead) or Full Cure (if the character is still alive) on one character for 50MP. That's half the price of either Full Cure or Life 2. Very useful. Get these from the Pollenseltas in the crater by manipulating them (on the right path, the women who use frozen breath, fascination, etc.)

Dragon Force- Not that useful. Raises Defense and Magical Defense of one character. Get this by manipulating Dark Dragons at Final Crater.

Death Force- Prevents suddon death attacks. Good against enemies you expect to use that, and when you're learning Roulette. Learn this from the Adamantine on the beaches of Yuffie's continent.

Flame Thrower- Fire damage to a single opponent. Get this from the flying creatures in the Mythril cave.

Laser- Same effect as Demi2, cuts enemies HP in half. You can get this from the card-jokers near Corel or from Dark Dragons at crater.

Matra Magic- Non-elemental damage on all opponents. Great at beginning of game. Get it from the custom sweepers right outside Midgar city.

Bad Breath- Similar to Hades, except without the damage. Hits all opponents with every status effect in the book. Get this from the Malboros on the mountains on the way to the Crater.

Beta- Fire damage to all enemies equal to Fire2-Fire3. Get this from the Midgar Zolem by getting him to less than 1000 HP. He will cast it on all characters. Ouch. Use Fire ring to get it early in the game and survive. Then, use it straight back on him to kill him!

Aquabreath- Water damage to all enemies. Very strong. Get this from Jenova-LIFE. If you missed it when you fought her, there is another monster that has it. Search the internet for it.

Trine- Lightening damage to all enemies equal to Bolt2-Bolt3. Get this from the Materia Keeper in the mountains on the way to Rocket Town, from Godo (Yuffie's father), or from the Stilvas on the way to the crater (the first time).

Magic Breath- Strong Tri-elemental damage to all opponents. The Stilvas in the mountains on the way to the crater cast this.

????- Does damage equal to Max HP - Current HP to one enemy. Useful halfway through through the game. Learn this from the Behemoths in the road to Shinra or from the Jerseys in the Shinra Mansion in the same room as the hidden stairway down to the library. Note: Don't attack Jersey. He will change to a second mode where he will not use ????. Goblin Punch- Damage ~attack to one opponent. Not that useful, but I think if you are using Ultima WEAPONS and it won't do much damage because you are low on HP or MP (certain characters only) then it will work, because I think it is based on strength, not your weapon. Get this from the Goblins on the Goblin Island in the NE.

Chocobuckle- This is useless. Supposedly strengthened the more you run. Tiny non-elemental damage to one enemy. To get this, buy three Mimmet greens. Then, go down by Mideel and get a chocobo in battle. Then feed it 1 mimmet green. Then, with the character who you want to learn chocobuckle with, use Level 4 suicide. It will counterattack on that character with Chocobuckle. Repeat for other characters. Note: Although this might sound like a silly rumor, it is true.

Level 5 Death- Kills any enemys with a level of 5. Learn this by manipulating Parasites in Final Crater. Cast Death Force on any level 5 characters first.

Death Sentence- Another pretty useless one. Targeted opponent dies after 60 seconds. Get from enemies on the rocky paths between the Ancient Forest and the City of the Ancients, or in the Gi cave.

Roulette- Kills a random character/enemy. Not that useful. Learn from Death Dealers (Joker-type guys) in Final Crater. Use Death Force first on all characters.

Shadow Flare- Extreme damage on one enemy. Get this from Ultima WEAPON, Ruby WEAPON, or from the Dragon Zombies on the right path at the crater. They don't use this when they die. I think they use it whenever they get hit hard, but it might just be random.

Pandora's Box- Damage approximately equal to Ultima on all enemies. Get this from the Dragon Zombies on the right path at the crater... I think they cast it occasionally when they die.

Supernova- There's a rumor that if you get all other enemy skills, you can learn Supernova from Sephiroth in the final battle and cast it back on him.