The May 20th episode of Marvel's most controversial (and hated?) show, Ultimate Spider-man, which was dubbed "Freaky" has been replaced by "Field Trip"
While "freaky" revolves around Wolverine and spider-man accidentally switching bodies, "Field trip" takes the shield teen heroes to asgard to battle loki and help Thor, who was changed to a frog, regain his original form.
Below is disneyXD's summary of the May 20th episode "Field Trip":
Field Trip:
When a simple class field trip leads Spider-Man and his fellow teen super heroes into an Asgardian adventure, they may be the only hope for Thor to stop his brother, Loki, from taking the throne of Asgard, in a new episode of Ultimate Spider-Man, Sunday, May 20 (11:00 -11:30 a.m., ET/PT) on Marvel Universe on Disney XD.
The reason of such change are unknown, but they might be due to the Avengers Movie success, pushing show runners to show kids Thor and Loki in their Ultimate Spider-man animated form.