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Undertale: Testing Grounds.

Undertale: Testing Grounds.

A Roblox experience owned by zeevee studios.

Fighting & PvPENSansUndertaleFighting

Description (written by the developer; not a statement by this register)

this is one of those games where your a sans and you play as sans to be the best sans and theres other sanses and you kill all of them. wow, that took a dark turn. the people working on the game right now are azreal_dreemar (creator) alternatemyths (asset maker) fortnite_3262 (general edits) and, of course, catpawlink (literally does nothing he didnt even ask to work on this). update: new model, check the lobby to test it. known issues: Bone zone will stay if not despawned after player death| Health Bar Will Damage You and make you regen to the set health for morphs.

Last updated by the developer 24 Sept 2022, 00:41 UTC.

0
playing (measured 12 Aug 2026, 21:03 UTC)
2,809
lifetime visits
52%
liked (14 👍 / 13 👎)
48
favourites (17.1 per 1k visits)
1 April 2021
created (per Roblox)

Play on Roblox →

Live players over time

Growth

Growth history is still building. We hold one measurement for this entry. A trend needs at least two, taken days apart — so this will fill in on its own rather than being estimated. We do not publish numbers we have not measured.

Measurement log — every players count we have recorded
Measured (UTC)PlayersChange
12 Aug 2026, 21:030first reading

Concurrent players at each of our measurements (insert-on-change).

Monetization — game passes

Fatal Error Sans
150 R$
Flowey
99 R$

Game passes for sale and their prices, measured from the Roblox passes API. Developer products bought inside the game aren’t publicly listable.

Badge funnel

You Joined. · welcome857 · 0.00% win
Mystery bro · secret41 · 0.00% win
Mirrored Insanity (EVENT) · other37 · 0.00% win

How many players have ever earned each badge — a proxy for how far players get before they stop. Steep drop-offs mark where a game loses people. Win rate is the past-day share of players who earned it; categories are assigned by a language model from each badge’s own name and description.