Ok so here’s how I imagine it working (complete with fun mockups):
Basically, you put it on and at first it just looks like normal armour but made of meat. However, there’s a three-barred “corruption” meter that fills up as you wear it and goes down when it’s unequipped. Each bar represents a different stage of the armour’s effects:
Stage 1 locks off the first four slots of your toolbar (you can still access the slots from the Inventory Screen so you can swap your items into the remaining ones) and replaces them with four abilities that can be selected like items and activated with right-click.
Self-Consume (sacrifice your health for hunger, with one heart equalling one drumstick.)
Blood Vision (see mobs through walls similar to Dark Vision 1 from Dishonored. Different mobs are highlighted in different colours; Passive are Green, Hostile are Red, Neutral are Blue and Bosses are Yellow.)
Blood Drain (drain the health from a mob, replenishing your own.)
Tentacles (auto-aiming high-damage tentacles that drain your health at a rate of half a heart every five seconds.)
Each ability also fills the Corruption Meter by two when used.
Stage 2 increases the player’s speed and damage. However, Villagers become afraid of you and Iron Golems instant-attack, and the screen gets a slight red tint. Oh yeah, also the armour becomes unremovable and the textures change to give the helmet a giant eye.
Stage 3 makes the armour take control. It attacks everything around it with the Tentacles power for two minutes until it finally reaches
Stage 4. In this stage, the armour detaches and becomes a boss called The Symbiote. It steals all the items stored in your first four slots and gains abilities based on what type they are.
Blocks: The selected block is summoned above the player and falls, dealing damage based on the block’s Hardness.
Plants (including leaves): The Symbiote spawns a patch of the plant, with relevant effects; Overworld flowers and grass apply Slowness, Nether plants burn, Mushrooms and Fungi apply Poison, Coral and Berry Bushes deal damage and Wither Roses apply Wither.
Items: Thrown at the player. Ingots and Gems deal more damage. Nether Stars apply Wither. Eggs summon Symbiote Chickens that swarm the player. Fire Charges set them on fire. Ender Pearls teleport the Symbiote.
Weapons/Tools: Wielded. Flint And Steel allows it to spawn fire.
Potions (including Splash and Lingering): The Symbiote drinks positive potions and throws negative potions. Dragon’s Breath creates the eponymous effect at the spot where it lands.
Food: The Symbiote eats/drinks it.
Misc: Spawn Eggs are thrown at the player and summon their respective mob. If a Symbiote somehow equips a portal, it throws it at the player, sending them to the respective dimension. A Symbiote in a stack throws whatever mobs are above it at the player.
On death, a Symbiote drops Purified Fleshite Armour that doesn’t have the weird effects.
(I hope this gets a lot of notes since I spent about an hour writing this and editing all the images for it and I was playing a videogame and literally stopped just to do this)