The t-shirt deal of the day over at RIPT Apparel today is a mash-up of Doctor Who and Space Invaders called “Invader Who.”

The tee, by artist Megan Lara, is on sale at RIPT only for today, Monday January 3, 2011 until tonight at midnight CST. Once the time is up, the shirt will no longer be available at the site.

The t-shirt is available in both men’s and women’s sizes in Black for $10. Kids sizes are $15 (Boys, Girls & Toddlers in Black); Onesies are $18 (in Black). You can also get the design on a Hoodie for $38 (in Men/Unisex sizes in Black).

The design takes the pixel aliens from the 1980’s arcade game Space Invaders and puts them together with a pixeled Dalek from Doctor Who.

You can view more of the artist’s work over at her Red Bubble page, which includes a really great Doctor Who t-shirt based on the The Weeping Angels.