Bubble
The stretch of a tournament immediately before the money, where the next elimination decides who leaves with nothing and who cashes.
ICM pressure peaks on the bubble, because the gap in real value between busting and min-cashing is enormous relative to the chips involved. A short stack close to the money has every incentive to fold and let someone else bust first, while a big stack can apply that exact pressure by shoving into stacks that cannot afford to call, even with a fairly ordinary hand.