Marvin, Murderous Mimic | Splinter Twin

Cards

Marvin and
Splinter Twin on the battlefield (
Splinter Twin attached to any creature you control not named
Marvin, Murderous Mimic).
Marvin does not have summoning sickness.

Activate
Marvin using the creature with
Splinter Twin attached's ability by tapping
Marvin, causing you to create a token copy of
Marvin with haste.
Put the tapped
Marvin into your graveyard due to the legend rule.
Repeat.