Boggles are fey pranksters, called to the material plane by people’s loneliness. You might say they’re the embodiment of the desire to get attention—any kind of attention, including negative. This may remind you of someone you know.
Boggles have low Strength but exceptional Dexterity and above-average Constitution. Their melee attack is feeble, and they lack a ranged attack. Really, they’re incapable of seriously hurting any but the lowest-level adventurer. Therefore, they attack not to kill but simply to harass.
They have proficiency in Perception, Sleight of Hand and Stealth, along with 60 feet of darkvision and advantage on Perception checks that rely on smell, so they won’t operate in broad daylight but rather in twilight, at night and underground. They’re at their best in darkness, where their Uncanny Smell makes up for the penalty on seeing targets in dim light. They’re resistant to fire, which has no meaningful bearing on their tactics.
Their skin secretes (not “excretes,” as it says in Volo’s Guide to Monsters . . . eww) either slippery or sticky oil. The former helps them slip out of enemies’ grasp; the latter makes it harder for enemies to slip out of theirs. Also, slippery oil helps them squeeze through narrow spaces, while sticky oil allows them to cling to walls and ceilings. This oil is always present, and a boggle requires a bonus action only to switch between the two types (kind of like Lúcio’s Crossfade ability).
Another bonus action available to boggles is Dimensional Rift, a “tunnel” up to 30 feet long that they, and only they, can move through, see through and bring objects through. Once created, a rift lasts until the end of the boggle’s next turn. The catch is that there has to be some kind of “frame” to create the rift in: a window or door, a hole in a wall, a fireplace, an oven door, a ladder, the end of a sawhorse, the underside of a raised bed, the mouth of a basket or amphora, a hollow in a tree, even the body and legs of a Medium or Large animal. Anything will do as long as there’s a solid perimeter around the rift space, no more than 10 feet on a side.
Finally, there’s the Oil Puddle action. Again, the boggle has a choice between slippery and sticky; it fills the boggle’s square or hex and lasts for an hour. Given enough time, a boggle can oil up several squares or hexes, creating a larger puddle. A slippery puddle requires anyone moving into or through it to make a Dexterity saving throw or fall prone; a sticky puddle requires a Strength saving throw against being restrained.
Boggles’ low Strength suggests that they should seek safety in numbers, but the flavor text in Volo’s seems to imply strongly that they’re solitary. Here are some ways boggles may use their constellation of features:
- In dim light or darkness, a lone boggle may Hide in the shadows using Stealth near a puddle of slippery or sticky oil. Attack while unseen—this won’t do any more damage, but it will at least give the boggle advantage on its attack roll. Attack again if the target slips and falls or gets stuck in the oil. Once the target manages to get up or get free, Attack one last time (action), then open a Dimensional Rift (bonus action), pass through it and run away (movement). (Remember that there has to be a frame present for the Dimensional Rift.)
- A boggle may create a Dimensional Rift (bonus action) and reach through it to filch an item from a victim using Sleight of Hand (Use an Object action), then run away (movement). If pursued, it will pass through the narrowest space available and create an Oil Puddle (action) in that space to impede its pursuer(s).
- A boggle may open a Dimensional Rift (bonus action) that allows it to reach a victim and pummel him or her through the rift (Attack action), then run away (movement). It can do so without incurring an opportunity attack, because the target can’t attack back through the rift!
- A fleeing boggle will beeline toward the nearest thing that can constitute a frame for its Dimensional Rift and use it to gain an extra 30 feet of movement, in addition to Dashing.
- One boggle in a group of them may act as a vanguard, perpetrating some act of mischief; when caught, it runs toward the rest of the group, which has already treated the ground with slippery or sticky oil. When the vanguard boggle’s pursuers slip or get stuck in the oil, the rest of the group pelt them with rocks (same attack modifier and damage as the boggle’s pummel attack), then run away.
Boggles aren’t made for sustained combat: they’ll Dash away immediately upon taking any amount of damage, however minor.
Boggles are no threat at all to most parties; they make better MacGuffins than villains, leading player characters into other situations or settings. They can also be employed as comic subplots and running gags. If you have a Beastmaster ranger in your group, you can get a lot of mileage out of a boggle that’s decided its calling is to torment that ranger’s animal companion.