Yes. DMT is terrifing!
Even A. Shulgin says he feels this way.
The function of a healthy ego is to make survival based descisions; "now it's time to eat. I'm tired, I think I'll get some rest. I'd better dress warm because it's snowing outside..." ect., ect.
So the healthy ego's primary purpose is survival.
It follows that the functional, healthy, ego isn't going to take dieing lightly. One can't expect to silence the id and have it just resighn peacefully...it's whole purpose in life is to continue living.
Meditation and DMT are two of the many tools used to reach states of higher consiousness. This involves silencing the mind and since the ego manifests itself primarily as noise (be it our mouths making 'I' statments, or our endlessly creeking internal dialog) it is akin to the (temperary) death of the ego.
Whereas meditation can take a long time to reach this little death called silence and, often results in all kinds of mystical phenomena, (sometimes known as Dharana, Dhyana, crossing the abyss, Epiphany and a lot of others and is said to grant 'Siddhis' or 'powers', all of these being an atempt on the part of the ego to continue living and to not be silent or die) DMT is quite fast acting and is terrifying to the ego.
I feel compelled to note that DMT is only a window though. Meditation is the door. Both require disapline to do continualy however.