I banged on the door against the glass so hard it cracked, and the crack spread a web that caught my skin for a moment and held it fast.
我使劲狠敲门上的玻璃，由于用力过猛，玻璃竟裂成网状，还一度紧紧夹住我的皮肤。
英语百科
Crack spread
Crack spread is a term used in the oil industry and futures trading for the differential between the price of crude oil and petroleum products extracted from it - that is, the profit margin that an oil refinery can expect to make by "cracking" crude oil (breaking its long-chain hydrocarbons into useful shorter-chain petroleum products).