Anyone identify what this might be please

[AstrantiaMajor]

It seems like some sort of hard shell which has burst open. Suddenly appeared in the garden.

Is it a bulb or a potato which has started to grow?

I does not seem like a bulb because it has a hard green shell. but I am now wondering if it is a bluebell.

Looks like a seed has germinated.

It is quite big, about the size of a button mushroom.

Plant it in a pot and see what happens - hopefully it is not a triffid!

Looks like an avocado maybe?

More hoping for cannabis

Looks like a bluebell growing out of an acorn shell. Can you tease the green bits out and see if they are growing separately from the shell, or part of it?

Looks like an avocado stone that's sprouted. Found a couple of these in my compost pile before. Sure if I was trying to cultivate them it wouldn't work!

Good plan Trethew, I will do it in the morning and report back.