Unknown things, as the name implies, unknown. How did they get here? What are they? Why are they all so different, but the same? All good questions, and we will never have the answers for them.
Unknown things are a high treasure, but strange Encounter Monster. You don’t fight them, but instead you are given a choice to engage with them, or follow their special to complete their little quest.
Below are all the Strange things, and their specials.

[Level 3]
Unknown Commitment
Discard your level 2, and level 5 Ability Cards. Collect the Monster.

[Level 3]
Unknown weight
Count your current treasure, if it’s over 215, collect the Monster.

[Level 3]
Unknown Strength
If 2 Ability cards are currently on Cooldown, collect the Monster.

[Level 3]
Unknown Redux
Face down and blind shuffle your slain Monsters. Turn over top 3 and add the total health together. If it’s greater than 21, Collect the Monster.

[Level 4]
Unknown Points
Add up all the Right-side Attack damage of your slain Monsters. If it’s greater than 23, collect the Monster.

[Level 4]
Unknown Blitz
In 3 turns, do 24 total Damage. Collect the Monster.

[Level 4]
Unknown Losses
If your health is lower than the person to your right, collect the Monster.

[Level 4]
Unknown Gains
If your health is greater than the person to your left, collect the Monster.