Doomtrain
Elemental: Poison (casts abnormal status)
Starting Level: 28
Starting HP: 2521
Where do I get it? First you have to find a ring called the Solomon Ring at Tears' Point in Esthar. Then you'll have to go out and get six Malboro Tentacles, six Remedy+'s, and six steel pipes before you can use the ring. Once you have done all that Doomtrain will accept your ofer and join you. (First available in Disk Three)

GF Attack: Runaway Train: This attack casts all sorts of abnormal statuses like Poison, Darkness, Silence, Berserk, Sleep, Doom, Curse, Petrify, Confuse, and Vit 0 on the enemy and is especially effective on humans. Even though some enemies might be immune to poison and absorb the damage its still worth it to send Doomtrain on it to inflict all those abnormalities.

Useful Abilities: Junk shop is one that i think is really cool since it lets you visit a weapon shop right through your menu instead of traveling to one. Doomtrain is also a big junctioning GF that comes with Elem-Atk-J, ST-Atk-J, Elem-Def-Jx4, and ST-Def-Jx4. There's also the useful autoshell.
Ability List
Ability

Elem-Atk_j
ST-Atk-J
Elem-Defx4
ST-Def-Jx4
Magic
GF
Draw
Item
Darkside
Absorb
Auto-Shell
SumMag+10%
SumMag+20%
SumMag+30%
SumMag+40%
GFHP+10%
GFHP+20%
GFHP+30%
GFHP+40%
Boost
Junk Shop
Forbid Med-RF
AP Needed

Learned
Learned
180
180
Learned
Learned
Learned
Learned
100
80
250
40
70
140
200
40
70
140
200
10
Learned
200
Leads To...

Nothing
Nothing
Nothing
Nothing
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Nothing
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Nothing
SumMag+20%
SumMag+30%
SumMag+40%
Nothing
GFHP+20%
GFHP+30%
GFHP+40%
Nothing
Nothing
Nothing
Nothing