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

Corrosive Form. A creature that touches the gelatin or hits it with a melee attack while within 5 feet of it takes 7 (2d6) cold damage. Any nonmagical weapon made of metal or wood that hits the gelatin 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 turned into freezing ice. Creatures holding the item take 7 (2d6) cold damage unless they have resistance or immunity.

Nonmagical ammunition made of metal or wood that hits the gelatin is destroyed after dealing damage.

The gelatin can eat through 2-inch-thick, nonmagical wood or metal in 1 round.

Spider Climb. The gelatin can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Ice Glide. The gelatin can move through nonmagical, unworked ice and snow as if it had a burrow speed of 60ft. It doesn't disturb the terrain while moving in this way 

Pseudopod. Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit: 22 (4d8 + 4) acid damage plus 19 (3d12) cold damage and the target must make a DC 15 Constitution Saving throw or be  encased in ice until the start of their next turn, and they use their action to thaw out on that turn. While frozen, they are paralyzed with full cover from spell attacks unless they involve fire. Fire nearby can thaw the creature early, but they do take fire damage if it contacts their body.

Impale. Melee Weapon Attack: +7 to hit, reach 10 ft., 1 target. Hit: 22 (4d8 + 4) piercing damage plus 19 (3d12) Cold damage. The creature is grappled by the gelatin. (escape DC 16) The gelatin can grapple up to 2 creatures at once. if it is grappling 2 creatures, it can't make this attack until they are ungrappled. While grappled the creaturee takes 3d12 cold damage at the end of each of their turns.

The gelatin has 2 Reactions, though it can't use two at once. It regains all of them at the start of each of it's turns.

Split. If a medium or larger gelatin is subject to Lighting or Slashing damage, it can split into two separate frosty gelatin. These copies are one size smaller than the one splitting and have half the splitters hit points (current and maximum)

Ice Block. If the gelatin is subject to any non fire damage, it can impose freezing ice on the part being attacked and reduce the damage by 2d10. If this would reduce the damage to 0, the gelatin counters the attack and does 2d10 cold damage to the attacker.