LittleJohnHook
RobinhoodRegisteredA factory-deployed Uniswap v4 launch-pool hook that takes an ETH-leg fee on all four swap shapes via beforeSwap/afterSwap return-delta. The fee optionally decays over time from a launch-time rate to a settled base rate. Fees are minted as ERC-6909 ETH claims to a per-pool locker. A configurable time-bounded sell-lock can restrict the creator from selling during the launch window. Pool config is write-once via factory; no owner or upgrade path exists.
What it can do
Its code executes inside each trade in pools that use it.
It can take or add tokens during a swap. Fees, burns and custom curves work this way, and so do scams.
Pools using it let the hook choose the swap fee instead of a fixed tier.
It runs when a pool is created, often to lock in that pool’s settings.