In the game mode above, I put survival, but this also works in creative too.
I was playing around with the /summon command, and I decided to try to summon a Giant for fun. However, I was in survival mode, so I heard the damage sound and then the game closed and the launcher opened up with the crash report. I then decided to try again, only this time in creative mode. When I launched the world, he wasn't there, so this time I /summoned him in the air, and the game didn't crash, until I made the made the mistake of flying into him, whereon the game crashed. When I launched up the world a couple of seconds later, he was still there, and this time I kept my distance. After playing around for a bit, I decided to try to force this to happen again. When I walked inside his head, nothing happened, yet when I flew into his torso, the game crashed again. I am not sure if it happens in other versions of Minecraft where the /summon command is in use, because this is the only version which I have tried.

What I expected to happen:
In creative mode-Nothing
In survival mode-Looking back, if I had thought about it, I would have expected to take damage.

What happened:
The game crashed

Steps to reproduce:
1. /summon a giant. It is useful to be in creative mode, however you can be in survival.
2.walk into his torso. I believe this works if you walk into his legs, because when in survival mode on the ground the same thing happened milliseconds after I had /summoned him, however, he could have been spawned slightly below the ground, because of his immense size.