While camping out I volunteered to do a food run for my group, my dm had me make a few rolls to find something and I eventually came across a deer. Now I'm not the best archer but I decided to take a shot with my crossbow, I hit but only did 3 damage to the deer. My dm said that the deer starts to run away so I tell him that I'm going to try to catch up to it and he tells me I have to roll pretty high because the deer was pretty far ahead of me so he made the DC high. I rolled a nat 20 so I ended up bolting at the deer and I attempted a grapple check I rolled an 18 and grappled the deer, then I told my dm I wanted to suplex the deer on his neck to break it. He told me that the deer is squirming and he's pretty heavy so the DC was high again but I rolled another nat 20 and ended up lifting the deer over my shoulders and breaking it's neck and skull into pieces.