Explain the Concept of a “Sandwich Attack” as a Specific Form of MEV Front-Running

A sandwich attack involves a malicious actor observing a large pending transaction (e.g. a token swap) in the mempool. The attacker then executes a small "buy" order just before the victim's transaction and a "sell" order immediately after it.

The victim's large transaction moves the price, allowing the attacker to profit from the resulting price difference between their two small trades. This effectively "sandwiches" the victim's trade, reducing the victim's realized price.