Prankster class draft

Was talking with Ali about this so here it is in disorganized writing

HP: a 1d8 class

Proficiencies
Weapon:simple melee
Armor: light
STs: Int, Con
Skills: 2 from Arcana, Nature, Perception, Survival, Performance

Features

At some level (7? 10?) pick between Fortune and Balance. Fortune embraces the randomness and fights entirely with monster forms, Balance uses less randomness, weaker monsters, can enchance base form and monster forms, more ability score improvement. Fortune CR caps at 16, Balance at 12/13?

Wheel of Fortune: 1 Action. The base class skill, you roll for a challenge rating with a probability distribution dependent on your level, then for a monster at random within that challenge rating and transform into it. You keep your int, personality, alignment, comprehension of languages (though depending on what you become you may not be able to communicate back) everything else is identical to the monster's description, your equipment drops on the spot. Can be used once every 6 hours (shares cooldown with Mimic and Humble Spin), lasts for said 6 hours, can be canceled with Undo Transformation but you still cannot reuse it until the original cd is out. When you roll on a challenge rating where no monsters exist, go down until you hit a valid one.
Currently the probability distribution is extrapolated from the following formula

Where bcr is your Base Challenge Rating, a secondary number assigned to the challenge ratings in this case (CR 0 to bcr 0, CR 1/8 to bcr 1 and so on). Currently you are at CR of 1/8 at lv1 and advance to the next each level. Will refer to your CR as bcr from here on, the secondary number is only used in the formula and the software.
In this case Low = 2, High = 3, index of a is your current secondary bcr.
What this means is: if you are level 3 your highest chance would be to hit Challenge Rating 1/2 with chance X (about 42% in this case if you solve it, in general approaches 40% if you solve the infinite series), Challenge Rating 1/4 is one lower so it would be X times 1/2 (2 in the power -1), Challenge Rating 1/8 would be chance X times 1/4 and so on, while Challenge Rating 1 has a chance of X times 1/3, Challenge Rating 2 is X times 1/9 and so on, Because of how exponents work that means you will be realistically hitting +/-3 from your base challenge rating, in fact every CR outside of the -5/+3 range has less than 1% chance of hitting, and gets exponentially smaller then further you go, but it's fun thinking what happens if you hit the lottery.

I know all that is complex to work with, so I made something to calculate it
https://dndpranksterspin.herokuapp.com/
put your level in and press enter or press the button, it will give you a monster and the (printed) page in the monster manual

The results can be viewed simultaneously by everyone who is connected to it as proof of the spin (no separate instances though)

Now that it's working it's not that big of a problem to modify the logic and values, but to modify probabilities I have to go back to matlab so if I am to change that it will be at another time. As it stands, at level 20 you will hit challenge rating 17 which is quite high so it does need modifications, but on lower levels it's mostly ok. There is also always the option of doing a standardized nerf on the monsters of higher ratings in some way.

Monster catalogue: A list of monsters. Starts empty, can be added to or have entries deleted due to use of the class abilities. No more than one entry per monster at a time.

Mimic: 1 Action. Level 5. ish.
Once every 6 hours transform into a monster you have previously transformed into with a CR equal to or lower than the base CR available to you 2 levels ago. Shares cooldowns with Wheel of Fortune/Humble Spin (meaning it's as if you have used wheel of fortune, cannot use wheel in the same 6 hours and vice versa even if it is canceled)

The main skill for out of combat interactions. The idea is that you build a catalogue of monsters randomly as you go along, hitting them with Wheel of Fortune and you can pick among those for their misc abilities (as long as their CR is low enough to qualify), at the cost of you having weak combat abilities for the rest of the duration. For example pick a monster that understands a certain language (though whether you'll be able to communicate back is uncertain), or pick a Mimic to transform into an object. Maybe it could have a lower CD/duration.

Undo Transformation: Level 3. 1 Action. Return to your original form. If you've taken damage while in monster form, your current health in base form is the same you had in monster form.

There are 1HP monsters that can't move out there. There are a bunch of creatures that cannot breathe out of the water out there. You'll die if you hit those with wheel of fortune. Until you hit level 3 that is. But before that, yeah, you are screwed, that's intentional because it's more fun that way. On a serious note, maybe carry some sort of water container, there is a decent chance you'll die without it.

Humble Spin: 1 Action. Level whatever-ish, it's not relevant at low levels anyways.
Roll as a lower level character (with the appropriate lower base Challenge Rating). Your rolls cannot go below that level's base challenge rating. Shares cooldowns with Wheel of Fortune/Mimic.

Basically what this means is: You are level 5 (base CR 2), you choose to roll as a level 3 (base CR 1/2). Every roll that hits below CR 1/2 is converted to CR 1/2. So a CR 1/8 will change to CR 1/2 before rolling for the monster.
There are 2 uses for that. Hitting lower CRs is more likely than higher CRs, so you may want to cut your potential loses and go for the safer CR-1 (so basically as a level 5 you roll as a level 4 and while you are 3 times less likely to hit CR 2, you are at least guaranteed to hit at least CR 1).
The real use though is rolling for a CR you can no longer hit or are very unlikely to hit so you can add monsters to your catalogue, in case you are eyeing an ability of a lower CR monster.
You can get that roll by enabling the Humble Spin option on the software and inputing the desired level (not your current one). The output will mention that was a "safe roll" to confirm it was a Humble Spin roll.

Power Spin (Fortune path): High level. Use Wheel of Fortune with bcr+1, lose X random monsters from your catalogue (if you have at least X)

Encore Transformation (Fortune path): High level. Transform into a monster from your catalogue. Delete that entry from your catalogue. Cannot use while under Wheel of Fortune's cooldown. After the 5th turn, at the start of your turn roll against 6 - con modifier + number of turns after the 5th turn (1 for first roll), return to your base form if you fail. If you transform again before resting, your new form's current HP is equal to the HP you had before you returned to your base form. You are considered to be under the effects of Wheel of Fortune for the duration of the transformation.

Pillaging Necrophagia (Fortune Path): Somewhere between lv12 and 16. If you eat an entire dead monster in monster form (or if the monster dies after being consumed), you can add it to the monster catalogue. Used once between long rests.

Apex Form (Fortune path): Lv17. Roll at bcr+5. Return to base form at the end of your turn. Any damage you took is inflicted to your base form upon returning. The monster is not added to your catalogue. Long rest between uses. Consume something expensive?

Thoughts

That's basically what I'm thinking of. You don't contribute much to combat outside of Wheel of Fortune. Your combat growth comes from your higher likelihood to access a better pool of monsters, while your out of combat growth depends on the things you have rolled previously. Practically only your int stat carries (but your proficiency on int saving throws does not) from your base character. Carrying more stats/skills/etc. or fixing probabilities more would make the monster forms a lot stronger which would require them to be balanced even more, which means less cool monsters. Maybe just some Ability Score Improvements would be fine to increase the CON of the base form just to survive before transforming.

I don't see this character lasting beyond level 2. One bad roll, like a Strige (2 HP), your character will likely be slaughtered in the first combat. In the normal state, your character isn't likely to survive combat without transformation. A simple Antimagic Field would cripple your character instantly.

If you want to transform into other animals, you should use a Druid (I suggest playing a set class so you can learn how to play D&D first before playing with a custom class so you can properly playtest any custom class and will strongly suggest this if you join). If you're deadset on use something like this custom class, then a monster list must be approved first.

In the earlier levels you basically have to be carried by your party if you get unlucky (you may even end up small enough to actually be carried), and yeah you can get unlucky enough to die. That's the point, you can get something good but it comes along with risk. At level 3 it's a bit safer since at least your rolls will stop being able to kill you directly. At level 5+ it's hard to get something that's too bad (you can get something subpar, but not something self-destructively bad), but you are supposed to make do, often with the help of others, if that's the case.

And wouldn't a caster have the same problem in an anti-magic field?

I still oppose of this custom class. If you want to change into stuff, again, I suggest Druid or some sort of already existing shifter class.

https://www.dandwiki.com/wiki/Shapeshifter_(5e_Class)

If you're going to join and play as a homebrew, this is what I'd approve of. There are more bad monsters than good, and I don't see your version living very long.