If a Gloom Confused you, and next turn a Magmar Smokescreened you, do you flip for Confusion or Smokescreen first?
Checking for Confusion should be the very first thing you deal with after announcing what attack you want to use. So as soon as you announce your attack, the check for Confusion happens immediately. If that passes, then you flip for Smokescreen's effect.
Source: WotC Chat (2000-07-13), TPCi Rules Team (2014-09-25), TPCi Rules Team (2016-01-07)

Relevant cards

Note: All applicable cards may not be listed below.
COL1_60
HGSS1_70
PL3_65