Restaking
Reusing already-staked assets to secure additional services, which adds extra rewards and additional ways to lose the same stake.
In a restaking system, stakers opt in to extra slashing conditions so that their existing bond also backs other services, such as oracle networks, data availability layers, or bridges. EigenLayer popularized the design on Ethereum. The economic point is that one pool of collateral can rent out its security several times; the corresponding risk is that a fault in any opted-in service can penalize the same collateral, so obligations correlate. Measurement suffers too: the same underlying asset can appear in staking totals, restaking totals, and the total value locked of a liquid restaking token, producing double counting across dashboards.
In practice
A staker who opts into several restaking services earns rewards from each while exposing the same bond to each service's slashing rules.
The common misunderstanding
Restaking does not create new collateral; the same stake is pledged more than once, so the yields add together and so do the conditions under which it can be seized.