Does a zero or negative Skyjo score double?
No. The Classic ender penalty applies to a positive round score.
Answer in context
An ender on zero or below keeps that result even when another player is lower.
You end the round on -3 and somebody else finishes on -5. You did not have the lowest score, but there is nothing to double: your round is recorded as -3. Doubling only ever applies to a positive total.
Do not turn -2 into -4 or zero into zero under a general doubling assumption; the rule specifically protects non-positive results.
This answer is for Classic Skyjo unless stated otherwise. Action and Junior may use different mechanics, and Voyage follows the original Classic gameplay.
Written in our own words and checked against the official rulebook. Skyjo.co.uk is an independent guide, not affiliated with Magilano. Spot an error? Tell us and we fix it.