Kairos
Καιρός
The god with a long forelock and a bald back of the head.
If Chronos is time flowing by, Kairos is "the one instant you must seize now."
The sculptor Lysippos carved him this way — wings on his feet, hair thick in front, smooth and bare behind.
The meaning: you can catch him as he approaches, but once he has passed, there is nothing left to grab.
Commonly confused
The saying "seize opportunity by the forelock" comes from here. He is often lumped together with Chronos, the god of time, but Kairos marks not duration — the right moment.