"生命极短暂的东西" can be translated into English as "things with an extremely fleeting/ephemeral existence" or, more concisely, "ephemeral beings/things" (though "beings" might lean more towards living entities; for objects or concepts, "things" is broader).
For a more poetic or literary touch, you could also say "things of a transient nature" or "brief, fleeting entities".
Ephemeral: Lasting for a very short time; transient.
Fleeting: Passing quickly; momentary.
Transient: Not permanent; temporary.
Choose the phrase that best fits the context and tone you're aiming for.