When my youngest was about five, she drew a few pictures of dead people and animals with Xs for eyes. I think she even drew Jesus this way. She sees the crucifix in church every Sunday - maybe that was the year she really took in the reason for Easter.
The drawings did look creepy and took me aback. But I knew she was a stable healthy child and she was just using a convention or a stereotype - like the sky being a blue line across the top of the page - because that’s the way children draw.
Somewhere between four and eight is when children start to get the concept of death and it’s a big concept to deal with. Not surprising they draw it sometimes.
My grandson was four when he asked if we could go in a rocket ship to visit with Jesus up in heaven.