Ragnarock - Go into ice cave and kill the weak deathworms there. Use a good shield to block their attacks and melee them with a sword, easy quick kills because they have so little health and they drop the same loot as a regular deathworm. Make sure to wear warm cloths.
Got a base made out of metal and a few turrets inside the base to farm black pearls get one shot in and insane xp drop over 3000xp and you get the horns for mantis tames like my lv 931 that 1v1 the manticore beta
I used a Rex to kill a Deathworm a few minutes ago...
For your assessment:
My Rex had 300% Melee Damage and 10,4k health
After our battle he had around 5k health left and I was able to kill another one because I forcefed him until 7k hp...
Don’t underestimate this worm ... :/