Not Stat Blocks, although those are related.
Stat Locks - fiendish magical locks that anyone can open, provided they are willing to temporarily let one of their stats drain a bit. Not too long, but just long enough to make a return trip from opening one or more a dangerous proposition.
Most DnDish games feature the same six stats: Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma. Even if your ruleset uses different amounts of stats with different names, these locks can still be used.
When discovered, a Stat Lock looks like raised block with a five-fingered handprint on it, for a right or left hand - it doesn't matter which. It is cool to the touch, and immediately activates when in contact with the flesh of a living being's hand. The first round drains whichever stat the lock is attuned to and changes color to red. It drains a point of the stat each round, changing colors from red to yellow to finally green, at which point it opens with a pop and a hiss.
Unless destroyed, the lock resets itself after 3 hours of first being activated, forcing the sequence and drain to begin anew. This 3-hour timer includes the time the lock is open, then it closes (the door with it, as well), and the lock resets.
Beings with hands can generally rotate through, each only losing a point before the next person slaps their hand onto the lock. Except for the rarer version that looks a bit like a metal glove you slip your hand into - these clench around the hand until the lock is full, then it releases.
Depending on how much is drained, this can be fatal.
Given the nature of these locks, they are typically only found in places that have plentiful minions, slaves, or prisoners because those employing these locks are not foolish enough to drain themselves.
But PCs are foolish enough, or at least willing to try - and that's what makes these locks interesting - they attack the character sheet. Note that regular use of such locks makes retainers and henchmen even more useful, although this will force loyalty checks.
Each lock requires a specific amount of a stat before opening (8 points is what most of my locks are), but some instead attack restfulness, leading to levels of exhaustion (4 levels is what I prefer, given that 6 levels kills a person - which is fine for NPCs, but perhaps a bit much for PCs).
While a long rest and some magics restore the stats at your rulesets various paces, this restoration eats up resources, which is the point of the exercise.
One lock might be bad enough, but they are often found in groups of 2, 3, 6, or sometimes all 7. And they all look the same - although close inspection under bright light reveals small runes and symbols that represent the drained stat.
The locks requiring two hands are often spheres or pyramids with handprints, while those with more may be found on a pillar or all in a row along a wall.
Or in any other configuration the room allows.
These locks are rarely found alone and are often tied into alarm systems that bring guards before the lock even opens. This becomes another decision point for players, because at least one PC will be occupied (back to the fight) opening the lock(s), while the others hold off trouble.
Note that locks such as these are not picked as much as opened by forcibly draining others - a guard pressing someone else's hand to the lock is unaffected, as the lock drains whomever hand is being held there.
Dispel Magic disables the lock, but does not open it. Knock opens the lock, but remember the close and reset time - which might be dangerous if everyone is inside the locked area when it reseals.
At the table, these locks force backwards math and maybe kill someone if a stat drops below 0 or Exhaustion hits level 6. In addition, players/PCs will go hunting a safe place to rest and regain their stats - or burn Restoration spells doing so.