final version without synergies

local Bombbugs = RegisterMod("BombBugs", 1)
local game = Game()

-- reference item and bomb

local bombBugs = Isaac.GetItemIdByName("Bomb Bugs")
local bombs = {} -- empty array of bombs

-- on player init

function Bombbugs:onInit()
	local player = Isaac.GetPlayer(0);
	if game:GetFrameCount() == 1 then
		if ((Game():GetLevel():GetStage() == 1) and (Game():IsGreedMode() == false)) then
			Isaac.Spawn(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_COLLECTIBLE, bombBugs, Vector(320, 250), Vector(0,0), player)

			-- spawn in test subjects

			-- Isaac.Spawn(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TAROTCARD, Card.CARD_TOWER, Vector(270, 250), Vector(0,0), player)  -- Tarotcard the tower, to check if the mod ignores normal troll bombs
			-- Isaac.Spawn(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_COLLECTIBLE, CollectibleType.COLLECTIBLE_FAST_BOMBS, Vector(370, 250), Vector(0,0), player)  -- Fast Bombs for fast testing
			-- Isaac.Spawn(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_BOMB, BombSubType.BOMB_SUPERTROLL, Vector(120, 150), Vector(0,0), player)   -- to check if the mod ignores Supertroll bombs
		end
	end
end
Bombbugs:AddCallback(ModCallbacks.MC_POST_PEFFECT_UPDATE, Bombbugs.onInit)

-- getting a bug on a bomb explosion


function Bombbugs:onExplosion()

	local player = Isaac.GetPlayer(0)    -- reference player
	local entities = Isaac.GetRoomEntities()    -- reference all room entities

	-- detect an explosion

	if player:HasCollectible(bombBugs) then
		for j = 1, #entities do    -- we check all entities in the room
			if(entities[j].Type == EntityType.ENTITY_BOMBDROP and entities[j].Variant ~= BombVariant.BOMB_SUPERTROLL and entities[j].Variant ~= BombVariant.BOMB_TROLL ) then   -- should be a bomb
				if(entities[j]:GetData().Exploded == nil) then    -- a fresh bomb
					entities[j]:GetData().Exploded = false   -- property that the bomb hasn´t exploded yet
					table.insert(bombs, entities[j])   -- insert the found bomb into the array
				end
			end
		end
		for j= 1, #bombs do   -- iterate through every bomb
			if(bombs[j]:IsDead() and bombs[j]:GetData().Exploded == false) then   -- if bomb is dead(has exploded)
				bombs[j]:GetData().Exploded = true   --	property that the bomb exploded
				local rng = player:GetCollectibleRNG(bombBugs)
				local roll = rng:RandomInt(100)
				if roll < 85 then
					Isaac.Spawn(EntityType.ENTITY_FAMILIAR, FamiliarVariant.BLUE_SPIDER, 0, bombs[j].Position, Vector(0,0), player)

				elseif roll < 95 then
					if(player:GetTrinket(0) ~= TrinketType.TRINKET_TICK and player:GetTrinket(1) ~= TrinketType.TRINKET_TICK and player:GetTrinket(0) ~= TrinketType.TRINKET_MATCH_STICK and player:GetTrinket(1) ~= TrinketType.TRINKET_MATCH_STICK) then   -- the game tries to give the player the Tick
						player:DropTrinket(player.Position, false)   -- if the player has a trinket it will be dropped
						player:AddTrinket(TrinketType.TRINKET_TICK)  --  add the tick to the player
					else
							Isaac.Spawn(EntityType.ENTITY_FAMILIAR, FamiliarVariant.BLUE_SPIDER, 0, bombs[j].Position, Vector(0,0), player)
							-- Isaac.Spawn(EntityType.ENTITY_PICKUP, PickupVariant.PICKUP_TRINKET, TrinketType.TRINKET_MATCH_STICK, bombs[j].Position, Vector(0,0), player)
					end
				else
					Isaac.Spawn(EntityType.ENTITY_SPIDER, 2, 1, bombs[j].Position, Vector(0,0), player)   -- spawns a red spider at a 5% chance
				end
			end
		end
		for j = 1, #entities do
			if(entities[j].Type == EntityType.ENTITY_BOMBDROP) then
				if(entities[j]:GetData().Exploded == true) then    -- the bomb, which is exploded
					entities[j]:Remove()    -- remove the original bomb
				end
			end
		end
	end
end
Bombbugs:AddCallback(ModCallbacks.MC_POST_UPDATE, Bombbugs.onExplosion)