Dominaria Spoiler Digest - Who's Who and What's What from the Release Notes
Whenever Tuktuk Scrapper or another Ally enters the battlefield under your control, you may destroy target artifact. If that artifact is put into a graveyard this way, Tuktuk Scrapper deals damage to that artifact's controller equal to the number of Allies you control.
3/1/2010 A token permanent that’s destroyed is put into its owner’s graveyard before it ceases to exist. If a token is destroyed by Tuktuk Scrapper’s ability, Tuktuk Scrapper deals damage to that token’s controller.
7/1/2013 If the targeted artifact hass indestructible or regenerates (or you choose not to destroy it), Tuktuk Scrapper doesn’t deal damage to that artifact’s controller. Similarly, if the targeted artifact is destroyed but a replacement effect moves it to a different zone instead of its owner’s graveyard, Tuktuk Scrapper doesn’t deal damage to that artifact’s controller.