Do defensive bonuses make any difference against Tar Monsters?
Solution 1:
After doing some investigation, the wiki seems to suggest that their attacks are technically impacted by ranged defense. However, when you consider the Lumberjack outfit takes up 4 slots (and is not very difficult to obtain), the remaining absolutely best in slot ranged defense is +124, with some pretty heavy and expensive gear (granite shield, infernal cape, amulet of fury, barrows gloves, ring of suffering (i)). In my case, the more practical best ranged defense is +99 (granite shield, cape of legends, amulet of fury, barrows gloves). Even with this, they still hit fairly accurately.
A lot of people cutting sculliusceps wear regeneration items instead; hitpoints cape, regen bracelet. Both of these double the regeneration rate, stacking to 4hp per minute (you can also regen at this rate with the rapid heal prayer and a regen bracelet). However, a regen bracelet currently costs 2,903,068 coins, and a hitpoints cape requires 99 hitpoints, so bringing a handful of monkfish, an antidote++, and logging in to the official world (321) to get targeted less often seems like the better way to go.