Ulalek trigger, causing you to pay ({C} magic symbol) ({C} magic symbol) to copy all spells you control and then copy all activated and triggered abilities you control, ensuring to put
Drowner of Truth's trigger on top of
Ulalek's trigger.
Resolve the copy of
Drowner of Truth's trigger, creating two 0/1 Eldrazi Spawn creature tokens.
Activate the Eldrazi Spawns by sacrificing them, adding ({C} magic symbol) ({C} magic symbol) .
Resolve the copy of
Ulalek's trigger, causing you to pay ({C} magic symbol) ({C} magic symbol) to copy all spells you control and then copy all activated and triggered abilities you control, ensuring to put
Drowner of Truth's trigger on top of
Ulalek's trigger.
Repeat from step 4.
Results
Infinite LTB.
Infinite ETB.
Infinite sacrifice triggers.
Infinite death triggers.
Infinite creature tokens.
Infinite magecraft triggers.
Infinite copies of abilities you control on the stack.