Cerbera odollam

The fruits look like unripe mangoes.

An excerpt from the article 15 facts about Cerbera odollam
They are large egg-shaped drupes up to 10 cm long.  Ripe fruits are dark red in color. After dropping, the skin of the fruit quickly darkens and disintegrates. The flesh is thick and fibrous, so the fruit floats easily and does not lose its ability to germinate.