diff --git a/NEWS b/NEWS
index 074df2bf8..0b7e290d1 100644
--- a/NEWS
+++ b/NEWS
@@ -78,6 +78,8 @@ DFHack future
                 replaces autoSyndrome
             reaction-trigger-transition.lua
                 a tool for converting mods from autoSyndrome to reaction-trigger
+            random-trigger.lua
+                triggers random scripts that you register
             skill-change.lua
                 for incrementing and setting skills
             spawn-flow.lua
diff --git a/scripts/modtools/random-trigger.lua b/scripts/modtools/random-trigger.lua
new file mode 100644
index 000000000..50d32b930
--- /dev/null
+++ b/scripts/modtools/random-trigger.lua
@@ -0,0 +1,171 @@
+--scripts/modtools/random-trigger.lua
+--triggers random scripts
+--register a few scripts, then tell it to "go" and it will pick a random one based on the probability weights you specified. outcomes are mutually exclusive. To make independent random events, call the script multiple times.
+
+local utils = require 'utils'
+local eventful = require 'plugins.eventful'
+
+outcomeLists = outcomeLists or {}
+randomGen = randomGen or dfhack.random.new()
+
+eventful.enableEvent(eventful.eventType.UNLOAD, 1)
+eventful.onUnload.randomTrigger = function()
+ outcomeLists = {}
+end
+
+validArgs = validArgs or utils.invert({
+ 'help',
+ 'command',
+ 'outcomeListName',
+ 'weight',
+ 'seed',
+ 'trigger',
+ 'preserveList',
+ 'withProbability',
+ 'listOutcomes',
+ 'clear',
+})
+
+local function triggerEvent(outcomeListName)
+ local outcomeList = outcomeLists[outcomeListName]
+ local r = randomGen:random(outcomeList.total)
+ local sum = 0
+ --print ('r = ' .. r)
+ for i,outcome in ipairs(outcomeList.outcomes) do
+  sum = sum + outcome.weight
+  if sum > r then
+   local temp = outcome.command
+   --print('triggering outcome ' .. i .. ': "' .. table.concat(temp, ' ') .. '"')
+   --dfhack.run_command(table.unpack(temp))
+   dfhack.run_script(table.unpack(temp))
+   break
+  else
+   --print ('sum = ' .. sum .. ' <= r = ' .. r)
+  end
+ end
+ --print('Done.')
+ --dfhack.print('\n')
+end
+
+local args = utils.processArgs({...}, validArgs)
+
+if args.help then
+ print([[scripts/modtools/random-trigger.lua
+Allows mutually-exclusive random events. Register a list of scripts along with positive integer relative weights, then tell the script to select one of them with the specified probabilities and run it.
+The weights must be positive integers, but they do NOT have to sum to 100 or any other particular number.
+The outcomes are mutually exclusive: only one will be triggered.
+If you want multiple independent random events, call the script multiple times.
+99% of the time, you won't need to worry about this, but just in case, you can specify a name of a list of outcomes to prevent interference from other scripts that call this one.
+That also permits situations where you don't know until runtime what outcomes you want.
+For example, you could make a reaction-trigger that registers the worker as a mayor candidate, then run this script to choose a random mayor from the list of units that did the mayor reaction.
+ 
+arguments:
+    -help
+        print this help message
+    -outcomeListName name
+        specify the name of this list of outcomes to prevent interference if two scripts are registering outcomes at the same time
+        if none is specified, the default outcome list is selected automatically
+    -command [ commandStrs ]
+        specify the command to be run if this outcome is selected
+        must be specified unless the -trigger argument is given
+    -weight n
+        the relative probability weight of this outcome
+        n must be a non-negative integer
+        if not specified, n=1 is used by default
+    -trigger
+        selects a random script based on the specified outcomeList (or the default one if none is specified)
+    -preserveList
+        when combined with trigger, preserves the list of outcomes so you don't have to register them again
+        it is extremely highly recommended that you always specify the outcome list name when you give this command to prevent almost certain interference
+            if you want to trigger one of 5 outcomes three times, you might want this option even without -outcomeListName
+        most of the time, you won't want this
+        will NOT be preserved after the user saves/loads (ask expwnent if you want this: it's not that hard but if nobody wants it I won't bother)
+        performance will be slightly faster if you preserve the outcome lists when possible and trigger them multiple times instead of reregistering each time, but the effect should be small
+    -withProbability p
+        p is a real number between 0 and 1 inclusive
+        triggers the command immediately with this probability
+    -seed s
+        sets the random seed (guarantees the same sequence of random numbers will be produced internally)
+        use for debugging purposes
+    -listOutcomes
+        lists the currently registered list of outcomes of the outcomeList along with their probability weights
+        use for debugging purposes
+    -clear
+        unregister everything
+]])
+ return
+end
+
+if args.clear then
+ outcomeLists = {}
+end
+
+if args.weight and not tonumber(args.weight) then
+ error ('Invalid weight: ' .. args.weight)
+end
+args.weight = (args.weight and tonumber(args.weight)) or 1
+if args.weight ~= math.floor(args.weight) then
+ error 'Noninteger weight.'
+end
+if args.weight < 0 then
+ error 'invalid weight: must be non-negative'
+end
+
+if args.seed then
+ randomGen:init(tonumber(args.seed), 37) --37 is probably excessive and definitely arbitrary
+end
+
+args.outcomeListName = args.outcomeListName or ''
+args.outcomeListName = 'outcomeList ' .. args.outcomeListName
+
+if args.withProbability then
+ args.withProbability = tonumber(args.withProbability)
+ if not args.withProbability or args.withProbability < 0 or args.withProbability > 1 then
+  error('Invalid withProbability: ' .. (args.withProbability or 'nil'))
+ end
+ if randomGen:drandom() < args.withProbability then
+  dfhack.run_command(table.unpack(args.command))
+ end
+end
+
+if args.trigger then
+ triggerEvent(args.outcomeListName)
+ if not args.preserveList then
+  outcomeLists[args.outcomeListName] = nil
+ end
+ return
+end
+
+if args.listOutcomes then
+ local outcomeList = outcomeLists[args.outcomeListName]
+ if not outcomeList then
+  print ('No outcomes registered.')
+  return
+ end
+ print ('Total weight: ' .. outcomeList.total)
+ for _,outcome in ipairs(outcomeList.outcomes) do
+  print(' outcome weight ' .. outcome.weight .. ': ' .. table.concat(outcome.command, ' '))
+ end
+ print('\n')
+ return
+end
+
+if not args.command then
+ return
+end
+
+--actually register
+local outcomeList = outcomeLists[args.outcomeListName]
+if not outcomeList then
+ outcomeLists[args.outcomeListName] = {}
+ outcomeList = outcomeLists[args.outcomeListName]
+end
+
+outcomeList.total = args.weight + (outcomeList.total or 0)
+local outcome = {}
+outcome.weight = args.weight
+outcome.command = args.command
+outcomeList.outcomes = outcomeList.outcomes or {}
+table.insert(outcomeList.outcomes, outcome)
+
+