After much thought, Jeff decides on something involving slime. The default settings for a Slime transformation weren't appealing to him, though, so he started typing out special instructions...
"The target will become slime-like; They'll retain their default form, but will be entirely slime. This also allows the ability to change form mostly at will, with some limitations."
"Although color can be changed, allowing the ability to appear mostly like whatever form is taken, the one thing that's uncontrollable is the transparency. The target will permanently remain transparent, regardless of form."
"Limitations regarding changing the target's shape are primarily regarding people or animals. In order to shift into the form of a human other than the target's original form, they must enter some part of the lower half of their desired form's body, and stay inside for half an hour"
"Upon gaining the form of a person wearing clothes, the clothing is ignored; The base shapeshifting forms are based on the complete nude variants of their basis, however clothes can be formed on top."
"The slime form is capable of squeezing into mostly any places, no matter the size, and still retain it's form at that time. It's often squishy and sticky to the touch. The form is also somewhat bouncy, but is capable of bringing things inside it as well. Those inside are still capable of breathing, despite the slime in the way."
"The target retains all of their senses, but in other human forms, they'll feel things the same as that person; This includes sensitivity in certain places. Some additional aspects may be retained from their form."
"When the transformation comes to it's end, they will remain in the same form they are in at the time the slime wears off, in the same place they were at the time."
He sets the time limit to one month, and starts thinking... "Should I use this on myself, or test it on someone else..."