Story time.

I was playing single player on the Center. I was trying to challenge myself so I decided that I wouldn't tame any flyers. I also decided that I wouldn't watch any videos about or on the map, since it was one of the few maps that I didn't know much about. I wanted to discover everything on my own. Not having flyers and not knowing resource and base locations made my progression a lot slower than usual, but I eventually made a base right across from the skull island, near that hill with a lot of metal and Crystal. My first half-decent tame was a level 90 Carno. This became my main traveling mount and my escort for the times that I was bringing metal down the mountain on my parasaur. I found a level 150 carno later when I was coming back from taming a sarco, but I didn't have everything that I needed to tame it so I went back to my base to make some more darts and a trap, but when I came back to the spot, the carno was gone. There wasn't much else in the area besides herbivores,and there was no body, so I am not sure what happened. We'll anyway, I kept exploring on my carno, and found a few cave entrances in the area. I wanted to go in on an imprinted and possibly mutated carno so that made me want to find a high level even more. One time I was exploring the edge of several islands with my sarco, and I came to the half volcano island with a bunch of carnos, so that made me take a closer look. But it wasn't the carnos that made me most excited. At the edge of the island I saw a level 140 carcharodontosaurus. I haven't ever tamed one but I have seen a few videos, and decided that right now the safest option to tame this would be to make a two sided trap with a behemoth gate between the sides. Trap the carch in one side and gain its trust then throw a cryo-sick creature (I chose brontos) out in the other side, unclain the bronto and kill it with the carch and repeat. So I went back to my base and started preparing.I already had one decent level bronto that I kept a temporary smelting base on for longer trips up the mountain. I used that to farm and smelt enough metal to make the gates for the trap( which is a lot harder to do without argies). Then I found another bronto to breed with and began the process of gathering 18 brontos with high health to feed to the Carch. I finished this whole process over several days, and when I finally finished I went back to the island and the carch was gone. Now with a carno, something could have killed that, but a Carch? I have noticed that on the Center, a lot of creatures end up under the map, so since creatures have disappeared on me twice I am wondering if that is how it happened. Anyway that I'd how I put hours of work preparing to tame a creature that just disappeared. That's Ark for ya.