Riddle

Sometimes I fly as fast as the speed of light. Sometimes I crawl as slow as a snail. Unknown until I am measured but you will certainly miss me when I'm gone. What am I?

Choose an answer

A.Sound
B.Speed
C.Distance
D.Time
Hint: It's a word with 4 letters, starting with "T".

Answer

Time

Why this is the answer

Time can feel like it flies or crawls depending on the moment, is only truly measured with a clock, and is always missed once it has passed.

This riddle is filed under "What Am I?" Riddles and rated Medium.