Artic Ooze

Amorphous. The ooze can move through a space as narrow as 1 inch wide without squeezing.

Corrode Metal. Any nonmagical weapon made of metal that hits the ooze corrodes. After dealing damage, the weapon takes a permanent and cumulative −1 penalty to damage rolls. If its penalty drops to −5, the weapon is destroyed. Nonmagical ammunition made of metal that hits the ooze is destroyed after dealing damage.

The ooze can eat through 2-inch-thick, nonmagical metal in 1 round.

False Appearance. While the ooze remains motionless, it is indistinguishable from any water source 

Pseudopod. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage plus 7 (2d6) acid damage, and if the target is wearing nonmagical metal armor, its armor is partly corroded and takes a permanent and cumulative −1 penalty to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10.

Drown. Melee Attack: Targets any grappled creature and focuses on drowning it until  it or its target is dead Target takes 1d8 cold damage if target can't escape in one round and than takes 1d6 Cold damage for every other round after the second round

STR:15  On success escapes the Ooze's grasp and falls out of the Ooze  

CON:15 On success target takes half damage  

If under 5 HP runs away from attackers and back into the water