Ian, Chrono Archmage

When Ian, Chrono Archmage comes
Into play, Create a legendary enchantment
Token named "Temporal Nexus"
During an opponents turn, if you cast
A spell, activate an activated ability, or
Activate a mana ability, put a time counter
On Temporal Nexus.
Remove 12 time counters from Temporal Nexus,
end the turn and take you take an extra turn