Board Thread:Plants vs. Zombies/@comment-4357674-20150718133544/@comment-26862176-20150806173152

Every a second, a spikeweed deals 1 damage to each zombie that walks on it.

Assume that it takes 1.5s for a imp to go over a spikeweed, normally you'll see: 1) The imp gets on the spikeweed; 2) Almost immediately, the spikeweed deals 1 damage to that imp; 3) 1s later, the second damage takes place; 4) 0.5s after the second damage, the imp leaves the spikeweed.

If two zombies get on the spikeweed, you will see the following in chronological order: 1) A miner gets on the spikeweed; 2) Almost immediately, the spikeweed deals 1 damage to that miner; 3) 0.4s after the damage, the imp gets on the spikeweed; 4) 1s after the previous damage (0.6s after the imp gets on), the second damage takes place; 5) 1.9s after the first damage (0.9s after the second damage, 1.5s after the imp gets on), the imp leaves the spikeweed; 6) 2s after the first damage (0.1s after the imp leave), the third damage takes place.

In the first case, 2 points of damage are applied to the imp. In the second, the imp avoids the first and the third damage, and only the second damage is applied to the imp. That's what you observe.