Too Long; Didn't Read
One of the most striking features of smart contract development is the inability to change anything once the contract is deployed. As a sort of emergency eject button, EVM provided the SELFDESTRUCT opcode, which will disable the contract on the blockchain, at the same time withdrawing all funds from it. Usage of SELFDESTRUCT has been controversial, as it's said to break immutability. Also it has obvious implications for rug-pulls.