Marvel is planning a series of 20 Howard the Duck variant covers in April, and calling it "What the Duck?!" Month.  “This April is going to be WTD certified,” Marvel SVP Sales & Marketing David Gabriel said, tweaking Marvel’s Distinguished Competition, which had a "WTF Certified" month in April of 2014 (see "DC's Titles in April labeled 'WTF'").

The promotion is spill-over from the launch of Marvel’s new ongoing Howard the Duck series in March (see "New Ongoing 'Howard the Duck'"), according to Gabriel, who said, "There were so many talented artists eager to take a quack at drawing a Howard cover we couldn’t resist building an entire variant month around him."

The four issues with "Howard the Duck" variants reproduced in this gallery are:

All-New Hawkeye #2 -- WTD Variant Cover by Francesco Francavilla
Amazing Spider-Man #17 -- WTD Variant Cover by W. Scott Forbes
Rocket Raccoon #10 -- WTD Variant Cover by Rob Guillory
Uncanny Inhumans #0 -- WTD Variant Cover by Christian Ward

The other issues that will have "Howard the Duck" variants in April are:

All-New Captain America #6
All-New X-Men #41
Ant-Man #4
Daredevil #15
Deadpool #45 (a.k.a. Deadpool #250)
Guardians of the Galaxy #26
Hulk #14
Inhuman #14
Legendary Star-Lord #11
Ms. Marvel #14
S.H.I.E.L.D. #5
Silk #3
Spider-Gwen #3
Superior Iron Man #7
Thor #7
Uncanny Avengers #4