Displacer Eel (3.5e Monster)

"Worse than the fish in the local rivers are the eels. Some of them have heads as big as those of horses..."

Displacer Fish are, it turns out, merely the larval form of a much nastier brute. When the swarm begins to get to the appropriate age the fish turn on each other, mindlessly killing and devouring one another until only one is left, ignoring everything else until this is accomplished. At least it's assumed to be age. No one knows how old Displacer Fish get, or how to tell what age they are. It could simply be a chemical stimuli. It finds a hiding place and enters a state of suspended animation while it metamorphoses into its adult form. The time for metamorphosis is up to a few weeks. Scholars aren't certain because of the difficulty in watching a Displacer Eel in the wild. Displacer Eels get up to 12 feet long and can weigh several hundred pounds. They still do not have the ability to speak yet.

Combat
Displacer Eels tend to rely on Swim-By attacks, snipping at opponents bit by bit. Or luring them into traps, or against deadlier opponents that will allow the Displacer Eel to scavenge remains.

 :  Any melee or ranged attack targeting the Displacer Eel has a 50% chance of missing unless the attacker has some means of locating them other than sight. See Invisibility doesn't negate this but True Seeing does.

 :  Displacer Eels have a +2 Resistance Bonus to ranged magical attacks that specifically target them (except for ranged touch attacks).

Skills: Displacer Eels get a +8 Racial Bonus to Hide and Swim checks. They may always Take 10 on a Swim check, even if threatened or endangered. They may use the Run action while swimming in a straight line.