Do-It-Yourself Seraph
Oracle Text
Flying
Whenever Do-It-Yourself Seraph attacks, you may search your library for an artifact card, exile it, then shuffle your library.
Do-It-Yourself Seraph has the text box of each card exiled with Do-It-Yourself Seraph in addition to its own.
Card Rulings
1/19/2018 If Do-It-Yourself Seraph has the text box of another card, it has all the abilities and flavor text of that card.
1/19/2018 If anything cares about the text of Do-It-Yourself Seraph, consider all of its text boxes as if they were one.
1/19/2018 If Do-It-Yourself Seraph leaves the battlefield, it loses any text boxes it gained. If it returns to the battlefield, it will be a new object and won’t have those text boxes, either.
1/19/2018 If Do-It-Yourself Seraph has abilities that contradict one another, the most recently added one wins. For example, if Do-It-Yourself Seraph has the text boxes of both Beast of Burden (power and toughness equal to the number of creatures on the battlefield) and Psychosis Crawler (power and toughness equal to the number of cards in your hand). Do-It-Yourself Seraph’s power and toughness would be defined by the text box added most recently.
2. Search and exile Blightsteel.
3. Profit!
In short, piecing together a combo like Phyrexian Devourer + Walking Ballista onto Mairsil is extremely difficult. If Do-It-Yourself Seraph was made Commander, or even Constructed legal, I feel it would fit well without be considered a "broken" version of Mairsil. It's ability triggering on attack as well as a CMC of 6 gives your opponents ample time to deal with it, and fortunately there are no artifact targets that could instantly give it Indestructible + Shroud/Hexproof. The lack of Cage counters means that removal of any sort permanently disrupts any half assembled combos.
The card feels very balanced for normal play despite its rather unorthodox method of Skill borrowering. So many commanders have access to the gimmick of inheriting textbox abilities in one form or another like Lazav, Sakashima, Kraj, The Mimeoplasm, and Mairsil. Each of these are set apart from one another in some unique fashion. Do-It-Yourself Seraph could have done the same. A potentially unique "Build Around Me" Commander that was relegated to the looney bin.