Child Iron Ooze

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

False Appearance. While the ooze remains motionless, it can disguise itself as a defenceless creature e.g. a puppy in order to lure in potential prey. Any shape can be discerned as an illusion with a DC 10 nature check. All disguise illusions have a coppery sheen. 

Size Shift: The ooze can rearrange its shape to fill the shape of a tiny, small or medium creature 

Pseudopod. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage plus 4 (1d6) 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.