The Spring Trap bounces entities off the ground, effectively causing instant death to the entity that step on it. You can avoid them by destroying them in 1 hit but they look similar to grass so WATCHOUT! they can use multiple times.
a video about how it works:
+Bounce entity into a very high place – the clouds!. cause instantly dead if they don’t have slow falling or falling damages resistance,…
+Look like grass so you can place this in any fields
+Can be used for multiple times. can only be destroyed by getting damage.