Grump

A boy in green dungarees who wants to talk. He becomes "the thing the game is named after" once he "turns" — on day 4 at the latest, or earlier if you make him angry enough.

Stages and resentment

Resentment is capped at 130 internally, but nothing changes above 100 — once turned is true it stays true for the rest of the run. The game explicitly checks grump.turned everywhere, never the raw number, so hitting 100 early behaves identically to waiting for day 4.

What raises or lowers resentment

• Every night at nightfall (before he turns): the difficulty's nightly resentment (Gentle +8, Normal +11, Nasty +15), +6 more if you didn't talk to him at all that day, plus +0.8 × number of messes left uncleaned.
• Answering one of his questions: whatever that specific answer costs — see Grump's Questions — every option costs something, from 5 up to 20.
• Giving him back his green crayon: −15 (only possible before he turns).
• Cleaning up any mess, anywhere: −1.5 (this is the one thing that reliably calms him — "tidying up his school").
• Witnessing the Card Kid get taken: +3, because he notices you did nothing (there was nothing to do).
• The Big Boys Club cutscene resolving: −20, once, per run — see The Big Boys Club.

Behaviours, before he turns

• Wander (day) — ambles between rooms and near the player, occasionally settling into Watch for a few seconds if he has line of sight and you're close.
• Stalk (night) — follows at a distance, never quite arriving, and cannot enter a room lit above 0.62 brightness at all. Occasionally knocks on your classroom door if you're inside it and he's close (every 22–40s). If the power ever goes out while you're somewhere fully dark, he moves to Loom right next to you, breathing, until the lights come back or you reach some brightness.
• He can relocate to somewhere unseen and nearer to you if you're far away and out of his line of sight (every 20–44 seconds) — he does not need to walk there.

Behaviours, once turned

• Charges the instant he gets a clear line of sight on a target — speed ×1.45, plus a stinger and a fear spike for whoever he's charging.
• Camps outside a hiding spot if he ends up within about 4.2 units of someone hidden, breathing (every 2.4s) for 7–12 seconds, and catches you if you come out early.
• Pops light bulbs he walks under, roughly every 9–18 seconds, disabling that fixture for 25 seconds.
• Screen fills with static and a heartbeat/drone rises the closer he gets ("dread").
• Relocates to somewhere nearer and unseen if a target is far away and out of sight (every 20–34 seconds).
• Repeats your own answers back to you — about 45% of the time when he speaks, he quotes one of the last 8 things you told him, verbatim.
• Ceiling lights still slow him at night (half speed while under one), and long enough under them (4–10 seconds, rising with the night) makes him retreat for 6 seconds. Daylight lights do not slow him at all.
• Hunt speed: clamp(3.3 + night×0.18, 3.3, 5.2), ×0.85 during the day.

If he catches you

Grump deals 62 damage (versus Bob's 28), a jumpscare of his face fills the screen, your fear maxes out, and 70% of the time he also takes one of your already-safe toddlers back out of the classroom as an extra cost. See Events & Encounters for the exact jumpscare mechanics.

Where he starts the day and night

Every morning he's placed inside a random non-hallway, non-outdoor, non-your-classroom room, at a random point inside it — but only after checking the spot is clear of furniture and has a walkable path to your classroom (fixed in commit df20bce, which also stopped his placement from ever landing him inside furniture). On a night with the He Is Closer modifier, he instead starts just outside your classroom door, subject to the same clear-and-reachable check, and is guaranteed never to start inside your own classroom.

Where he can be seen

Grump only appears on the map while it's daylight and before he's turned — see The Map.