I converted the 2E version of it as a giant (being Large in the 2E MC Annual Vol 2.). Here's my version if it helps at all.
Umpleby
Large Giant
Hit Dice: 6d8+18 (54 hp)
Initiative: -1 (Dex)
Speed: 20 ft.
AC: 16 (-1 Dex, -1 size, +8 natural)
Attacks: Slam +8 melee or net +3 ranged
Damage: Slam 1d4+7 or net (see text)
Face/Reach: 5 ft by 5 ft/10 ft (30 ft with ropes)
Special Attacks: Electrical shock, nets
Special Qualities: Electricity immunity, detect treasure
Saves: Fort +10, Ref +1, Will +2,
Abilities: Str 21, Dex 8, Con 16, Int 6, Wis 10, Cha 6
Skills: Listen +2, Rope Use +3, Spot +2
Feats: Great Fortitude, Power Attack
Climate/Terrain: Temperate Forest
Organization: Solitary or Family (1-3)
Challenge Rating: 5
Treasure: Standard coins, standard goods (gems only), no items
Alignment: Usually neutral
Advancement: By character class
ECL: +8
An umpleby appears as a giant, vaguely humanoid, hulking mass of orange fur with only two dull-looking eyes and a drooping mouth visible underneath the fur. The average umpleby is 8 ft tall and weight 400 pounds. Bits of static electricity can occasionally be spotted emitting from the creature’s fur. Rather stupid but peaceful, the umpleby seems apathetic to most creatures it meets but occasionally decides blunder around following an adventuring party along as a neutral observer. It is very fond of shiny gems and coins and values only these as treasures. The loyalty of an umpleby (for what it is worth) can be easily bought by offering it food or water, as it is not the most efficient consumer and hunter with all of its fur.
Combat
A umpleby rarely, if ever initiates an attack, but it will defend itself if attacked by attacking with its powerful fists or ensnaring its opponents in nets made of its voluminous furs and shocking them.
Electrical Shock (Ex): With its great mass of fur, an umpleby generates a great amount of static electricity. It can hold up to 50 points of electrical damage at once and may release this electrical energy at any rate it chooses. To shock an opponent, all an umpleby has to do is hit with a simple touch attack or conduct it through its ropes. After using up all its electrical energy, an umpleby immediately lays down and sleeps, regenerating all 50 points of electricity if it sleeps for 8 hours or over, 37 points if it sleeps for 4-8 hours, 25 points if it sleeps for 1-4 hours, or 4d4 points if it sleeps for less than 1 hour but no less than 45 minutes.
Nets (Ex): A umpleby can throw nets made out of its fur at opponents up to 30 ft away. If the umpleby hits an opponent with this attack, a successful Escape Artist (DC 20) or Strength (25) check is necessary to escape the nets. The umpleby may conduct its electrical energy through the net in order to shock an ensnared foe.
Detect Treasure (Su): An umpleby automatically notices the presence of valuable amounts of coins and gems (1000 gp worth or more in coins or 50 or more gems) within 100 ft as a free action. If it concentrates for one round, it can pinpoint the general direction of where the treasure lies.
), that leaves us with these remaining critters from the FF, unless i missed something:
i really like the nets and the >BZZT< shock touch. 
