Sponge Contract

Name: Nameless; Referred to as "Nanashi"
Species: Sponge
Type: Sensory (Base);
Rank: E-A Rank (S-rank will be updated for it's increased abilities)
Elements: N/A
Relation: N/A
Physical Traits:
Description: The summoning of this form is very unique, and unlike any other creature. Due to the low form of the sponge, when summoned it requires but a fraction of chakra compared to the "Summoning Technique" and simply releases a small collection of pores through the finger tip. The small amounts released are absolutely useless at this level however, and will remain beneficial for the time. However, it will require chakra to increase their size (thus the summoning cost is low), as well as a good amount of water. Usually in the form of Water Release, applied liquids which touch this surface will result in a massive increase in reproduction, which will consume most of the water in a matter of seconds; this is because the sponges sensory nature draws it to chakra, so it will always grow towards large amounts of chakra, though it can only absorb Water. As the sponge gains more water, it will begin to produce itself more fluently, and be capable of reproducing itself on a larger scale, connecting to all the patches of Sponge which have formed throughout the area. (Usually applied through multiple 'Summonings'. The sponge itself provides a very sturdy defense, as it begins to grow. The sponge itself, no matter its rank, is naturally harder than stone, and provides a formidable protection. However it can only grow based on the water within the area, and will only grow when there is chakra present. - It also can be ineffective to the user as it will grow towards their attacks to, and likely stunt their effectiveness by getting in the way.

Eventually, when it has gained enough moisture, the sponge (over a course of time) will increase to form a massive done which the user can go into, forcing their opponent to chase after them. When the sponge has reached A-rank, the user can place their palm against the wall of the sponge and force it to manipulate, allowing them to change the battlefield to their advantage. At A-rank, most B-rank attacks can break formations of this sponge within range, though it will only force the sponge to continue growing, pitying the opponent in a strange position. The best counter for the sponge is to not use chakra, and simply go into a hand-to-hand battle, and overwhelm the user this way. Strength can be used to break the walls within the sponge. As well, it is not impossible to escape, as the user can only control the surrounding area within the sponge, and when their hand is removed from the sponges surface, it will revert back to normal. Because of this, there are plenty of holes which can be used to escape, if you can find your way through the maze.

E-rank Form: This is the stage it is placed within upon contact, but will immediately turn to D-rank when moisture is present.
D-rank Form: At this stage the sponge is capable of reproducing itself and increasing size. The volume it is increased by will be 50% of the water source it draws in.
C-rank Form: Once the mass of sponge has changed to roughly be enough to cover a human, it will increase to C-rank and be able to increase size by up to 60% from any water source.
B-rank Form: With the mass of sponge being enough to consume two large vehicles, its rank is increased to B-rank, and it can grow in size by up to 75% of any water source.
A-rank Form: This form is achieved when the sponge is over a 10m Radius (all together), and will begin growing on its own, very slowly. the sponge will increase based on any presence of water it absorbs, equal to that amount.

Approved. Note that for balance any sort of precise changes will require a jutsu and/or a clear chakra cost explanation to go with them. Moving walls and opening new doors are fine for no charge but for combat related ones like creating spikes, those will need some kind of required chakra cost.